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  • What speed are Wi-Fi management and control frames sent at?

    - by Bryce Thomas
    There are a bunch of different 802.11 Wi-Fi standards, e.g. 802.11a, 802.11b, 802.11g, 802.11n etc. that all support different speeds. Wi-Fi frames are generally categorised as one of the following: Data frames - carry the actual application data Control frames - coordinate when its safe to send/reduce collisions Management frames - handle connection discovery/setup/tear down (e.g. AP discovery, association, disassociation) My question is about whether all these frames, and specifically management frames, are transmitted at the fastest supported speed available, or whether certain classes of frames are transmitted at some lowest common denominator speed. I have noticed that when I put an 802.11b/g only device into monitor mode and capture traffic over the air, I still see management frames (e.g. association/disassociation) being transmitted between my phone and AP which are both 802.11n, even though 802.11n has a higher transfer rate. So I am imagining one of two possibilities: My 802.11n phone/AP had to negotiate a slower speed for some reason and that's why I can see their frames on my 802.11b/g monitoring device. Management frames (and perhaps control frames also?) are sent at a lower speed, and it's only data frames that are transmitted faster with newer 802.11 standards. The reason I would like to know which one of these two possibilities (or perhaps a third possibility) is the case is that I want to capture management frames, and need to know whether using an 802.11b/g card is going to lead to me missing some frames sent at higher speeds than the monitoring card can observe. If management frames are indeed sent at a slower rate, then it's all good. If I just happen to be seeing the management frames because my phone/AP have negotiated a slower rate though, then I need to reconsider what card I use for packet capture.

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  • How can I run Gnome or KDE locally in Cygwin?

    - by John Peter Thompson Garcés
    Apparently it is possible to do this using cygwin ports, as can be seen in screenshots. I followed this how-to to get apt-cygports set up, and I used it to install gnome-session. This how-to supposedly gives the commands needed to run Gnome or KDE, but whenever I try to run Gnome, a blank X-window pops up and then quickly disappears. Here is the terminal output: $ startx /usr/bin/dbus-launch gnome-session xauth: file /home/jpthomps/.serverauth.4168 does not exist Welcome to the XWin X Server Vendor: The Cygwin/X Project Release: 1.10.3.0 OS: Windows 7 Service Pack 1 [Windows NT 6.1 build 7601] (WoW64) Package: version 1.10.3-12 built 2011-08-22 XWin was started with the following command line: /usr/bin/X :0 -auth /home/jpthomps/.serverauth.4168 (II) xorg.conf is not supported (II) See http://x.cygwin.com/docs/faq/cygwin-x-faq.html for more information LoadPreferences: /home/jpthomps/.XWinrc not found LoadPreferences: Loading /etc/X11/system.XWinrc LoadPreferences: Done parsing the configuration file... winDetectSupportedEngines - DirectDraw installed, allowing ShadowDD winDetectSupportedEngines - Windows NT, allowing PrimaryDD winDetectSupportedEngines - DirectDraw4 installed, allowing ShadowDDNL winDetectSupportedEngines - Returning, supported engines 0000001f winSetEngine - Using Shadow DirectDraw NonLocking winScreenInit - Using Windows display depth of 32 bits per pixel winFinishScreenInitFB - Masks: 00ff0000 0000ff00 000000ff Screen 0 added at virtual desktop coordinate (0,0). MIT-SHM extension disabled due to lack of kernel support XFree86-Bigfont extension local-client optimization disabled due to lack of shared memory support in the kernel (II) AIGLX: Loaded and initialized /usr/lib/dri/swrast_dri.so (II) GLX: Initialized DRISWRAST GL provider for screen 0 winPointerWarpCursor - Discarding first warp: 637 478 (--) 5 mouse buttons found (--) Setting autorepeat to delay=500, rate=31 (--) Windows keyboard layout: "00000409" (00000409) "US", type 4 (--) Found matching XKB configuration "English (USA)" (--) Model = "pc105" Layout = "us" Variant = "none" Options = "none" Rules = "base" Model = "pc105" Layout = "us" Variant = "none" Options = "none" winBlockHandler - pthread_mutex_unlock() winProcEstablishConnection - winInitClipboard returned. winClipboardProc - DISPLAY=:0.0 winClipboardProc - XOpenDisplay () returned and successfully opened the display. xinit: XFree86_VT property unexpectedly has 0 items instead of 1 xinit: connection to X server lost waiting for X server to shut down winClipboardProc - winClipboardFlushWindowsMessageQueue trapped WM_QUIT message, exiting main loop. winClipboardProc - XDestroyWindow succeeded. winClipboardProc - Clipboard disabled - Exit from server winDeinitMultiWindowWM - Noting shutdown in progress

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  • Fix for php 5.3.9 libxsl security "bug" fix

    - by Question Mark
    just this morning i updated my debian server to php 5.3.9 , change log (last item in list) has a fix for this bug and now when running any hosted site using XSL transforms i get: Warning: XSLTProcessor::transformToXml(): Can't set libxslt security properties, not doing transformation for security reasons I'm not using any <sax:output> tags in my xslt at all. Does anybody have any information on this, current chatter about it is thin, so i'm i little lost. Using the suggestion about switching ini settings on and off either side of -transformToXml(): ini_set("xsl.security_prefs", XSL_SECPREFS_NONE) or $xsl->setSecurityPreferences(XSL_SECPREFS_NONE) brings me back to the same error Many thanks. Progress: - Upgrading libxml and recompiling libxslt against the new version was a good suggestion, though has not fixed the issue. - Compiling the latest php5.3 snapshot does not fix the issue. Solution: I'm unsure what actually solved this, very sorry for anyone else having the same problem. firstly i upgraded libxml, then applied a few patches, then went into php source for the xsl parser and added some debugging and a few tweaks, after a few compiles getting the configure args right the error went away and wasn't reproducible. I would definitely recommend upgrading libxml as Petr suggested below and then grabbing the latest snapshot from php.net.

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  • changing filesystem format from xfs to ext4 without losing data

    - by A.Rashad
    I have a fresh Lucid Lynx (Ubuntu 10.04) running on a laptop. where I defined the filesystems as: mount point / on ext4 (46 Gb) mount point /home on jfs (63 GB) swap as 3 Gb I left the machine over night to do some task, without AC power supply. next day in the morning I found it on standby, task completed, but filesystem was not reachable. it gave me I/O error it seems that there is a problem with jfs and standby. anyways, to avoid any hassle, I want to move this mount point from jfs format to ext4. can I do this without losing data and without the need to place the data in a temporary location until transformation is done? sorry to mention that, but I recall back in the windows days, we would change a FAT16 to FAT32 or a FAT32 to NTFS without having to lose the data. I hope this is available on Linux. Update The /home filesystem was xfs not jfs, and it seems there is a bug with this filesystem for some reason, I had to re-install the OS twice until I ended up with ext4 for the entire / However, as a conclusion, it seems that there is no way to make a conversion

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  • PHPMyAdmin: "General relation features: Disabled"

    - by Simón
    I've been looking around for something like this for a while, and I've found some tips on similar issues, but not exactly the same. I really don't know what to do. I downloaded and installed WAMP, and I have a MySQL and PHPMyAdmin setup according to common indications that can be found everywhere (securing MySQL root account, etc.). When I log into PHPMyAdmin (either as root or as pma), I see the following message at the bottom of the page: The additional features for working with linked tables have been deactivated. To find out why click here. And when following the link, got a page with the following: Server: localhost $cfg['Servers'][$i]['pmadb'] ... OK $cfg['Servers'][$i]['relation'] ... OK General relation features: Disabled $cfg['Servers'][$i]['table_info'] ... OK Display Features: Disabled $cfg['Servers'][$i]['table_coords'] ... OK $cfg['Servers'][$i]['pdf_pages'] ... OK Creation of PDFs: Disabled $cfg['Servers'][$i]['column_info'] ... OK Displaying Column Comments: Disabled Bookmarked SQL query: Disabled Browser transformation: Disabled $cfg['Servers'][$i]['history'] ... OK SQL history: Disabled $cfg['Servers'][$i]['designer_coords'] ... OK Designer: Disabled Somebody please explain to me, why the heck if all settings are "OK" the features remain "Disabled"? Note: at first all the settings were "not OK" and I managed to add the settings to config.inc.php, and then created the tables using scripts/create_tables.php. Of course I have already tried restarting the server or clearing the browser cache (several times, so I am sure the problem comes elsewhere).

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  • IPC between multiple processes on multiple servers

    - by z8000
    Let's say you have 2 servers each with 8 CPU cores each. The servers each run 8 network services that each host an arbitrary number of long-lived TCP/IP client connections. Clients send messages to the services. The services do something based on the messages, and potentially notify N1 of the clients of state changes. Sure, it sounds like a botnet but it isn't. Consider how IRC works with c2s and s2s connections and s2s message relaying. The servers are in the same data center. The servers can communicate over a private VLAN @1GigE. Messages are < 1KB in size. How would you coordinate which services on which host should receive and relay messages to connected clients for state change messages? There's an infinite number of ways to solve this problem efficiently. AMQP (RabbitMQ, ZeroMQ, etc.) Spread Toolkit N^2 connections between allservices (bad) Heck, even run IRC! ... I'm looking for a solution that: perhaps exploits the fact that there's only a small closed cluster is easy to admin scales well is "dumb" (no weird edge cases) What are your experiences? What do you recommend? Thanks!

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  • Sane patch schedule for Windows 2003 cluster

    - by sixlettervariables
    We've got a cluster of 75 Win2k3 nodes at work in a coarse grained compute cluster. The cluster is behind a mountain of firewalls and resides in its own VLAN. Jobs of all sizes and types run on the cluster and all of the executables running are custom-made. (ed: additional notes on our executables) The jobs range from 30 seconds to 7 days in duration, and may contain one executable or 2000 sub-jobs (of short duration). Obviously we are trying to avoid the situation where our IT schedules a reboot during a 7 day production job. We have scheduling software which accomodates all of the normal tasks for a coarse grained cluster and we can control which machines are active for submission, etc. If WSUS was in some way scriptable (or the client could state it's availability for shutdown) we could coordinate the two systems and help out. Currently, the patch schedule is the Sunday after Super Tuesday regardless of what is running on the cluster. We have to ask for an exemption every time we want to delay patching a machine for a long running production job. Basically, while our group is responsible for the machines we have little control over IT's patch schedule. Is patching monthly with MS's schedule sane for a production Windows cluster? Are there software hooks in WSUS where we could say, "please don't reboot just yet"?

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  • mod_rewrite changes case even if not matching RewriteCond?

    - by kirdie
    I have a really strange problem with my MediaWiki which I want to have articles of the form mywiki.org/MyArticle. Now I got most of it to work using the following code but it mysteriously cannot display the logo anymore. RewriteEngine On # don't rewrite valid requests to files and directories RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} !-f RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} !-d # mywiki.org/MyArticle gets rewritten to mywiki.org/index.php/MyArticle RewriteRule ^/(.*)$ /index.php/$1 [L,QSA] Now when I type in mywiki.org/img/logo.jpg in my browser the adress changes to http://wiki.geoknow.eu/Img/logo.jpg (capital I) and I get to the empty article page but the image is definitely there (in my document root under the img folder): /var/www/mywiki.org$ ls img logo.jpg So far so bad. But now it gets really crazy: When I add RewriteCond %{REQUEST_URI} !^/.*\.jpg my adress still gets rewritten and my access log says - - [05/Dec/2012:16:30:21 +0100] "GET /Img/geoknow_logo.jpg HTTP/1.1" 404 509 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Firefox/17.0" Where does that capital I in Img come from? The rule is not even executed because at least one condition is definitely not met now and I also don't have any to lowercase-transformation defined anywhere. What is happening there and how can I repair this? P.S.: Now all of the sudden the problem went away (the image is displayed as it should and there is no capital replacement anymore. What can cause this and why does it spontanously appear and disappear?

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  • Why is this class re-initialized every time?

    - by pinnacler
    I have 4 files and the code 'works' as expected. I try to clean everything up, place code into functions, etc... and everything looks fine... and it doesn't work. Can somebody please explain why MatLab is so quirky... or am I just stupid? Normally, I type terminator = simulation(100,20,0,0,0,1); terminator.animate(); and it should produce a map of trees with the terminator walking around in a forest. Everything rotates to his perspective. When I break it into functions... everything ceases to work. I really only changed a few lines of code, shown in comments. Code that works: classdef simulation properties landmarks robot end methods function obj = simulation(mapSize, trees, x,y,heading,velocity) obj.landmarks = landmarks(mapSize, trees); obj.robot = robot(x,y,heading,velocity); end function animate(obj) %Setup Plots fig=figure; xlabel('meters'), ylabel('meters') set(fig, 'name', 'Phil''s AWESOME 80''s Robot Simulator') xymax = obj.landmarks.mapSize*3; xymin = -(obj.landmarks.mapSize*3); l=scatter([0],[0],'bo'); axis([xymin xymax xymin xymax]); obj.landmarks.apparentPositions %Simulation Loop THIS WAS ORGANIZED for n = 1:720, %Calculate and Set Heading/Location obj.robot.headingChange = navigate(n); %Update Position obj.robot.heading = obj.robot.heading + obj.robot.headingChange; obj.landmarks.heading = obj.robot.heading; y = cosd(obj.robot.heading); x = sind(obj.robot.heading); obj.robot.x = obj.robot.x + (x*obj.robot.velocity); obj.robot.y = obj.robot.y + (y*obj.robot.velocity); obj.landmarks.x = obj.robot.x; obj.landmarks.y = obj.robot.y; %Animate set(l,'XData',obj.landmarks.apparentPositions(:,1),'YData',obj.landmarks.apparentPositions(:,2)); rectangle('Position',[-2,-2,4,4]); drawnow end end end end ----------- classdef landmarks properties fixedPositions %# positions in a fixed coordinate system. [ x, y ] mapSize = 10; %Map Size. Value is side of square x=0; y=0; heading=0; headingChange=0; end properties (Dependent) apparentPositions end methods function obj = landmarks(mapSize, numberOfTrees) obj.mapSize = mapSize; obj.fixedPositions = obj.mapSize * rand([numberOfTrees, 2]) .* sign(rand([numberOfTrees, 2]) - 0.5); end function apparent = get.apparentPositions(obj) %-STILL ROTATES AROUND ORIGINAL ORIGIN currentPosition = [obj.x ; obj.y]; apparent = bsxfun(@minus,(obj.fixedPositions)',currentPosition)'; apparent = ([cosd(obj.heading) -sind(obj.heading) ; sind(obj.heading) cosd(obj.heading)] * (apparent)')'; end end end ---------- classdef robot properties x y heading velocity headingChange end methods function obj = robot(x,y,heading,velocity) obj.x = x; obj.y = y; obj.heading = heading; obj.velocity = velocity; end end end ---------- function headingChange = navigate(n) %steeringChange = 5 * rand(1) * sign(rand(1) - 0.5); Most chaotic shit %Draw an S if n <270 headingChange=1; elseif n<540 headingChange=-1; elseif n<720 headingChange=1; else headingChange=1; end end Code that does not work... classdef simulation properties landmarks robot end methods function obj = simulation(mapSize, trees, x,y,heading,velocity) obj.landmarks = landmarks(mapSize, trees); obj.robot = robot(x,y,heading,velocity); end function animate(obj) %Setup Plots fig=figure; xlabel('meters'), ylabel('meters') set(fig, 'name', 'Phil''s AWESOME 80''s Robot Simulator') xymax = obj.landmarks.mapSize*3; xymin = -(obj.landmarks.mapSize*3); l=scatter([0],[0],'bo'); axis([xymin xymax xymin xymax]); obj.landmarks.apparentPositions %Simulation Loop for n = 1:720, %Calculate and Set Heading/Location %Update Position headingChange = navigate(n); obj.robot.updatePosition(headingChange); obj.landmarks.updatePerspective(obj.robot.heading, obj.robot.x, obj.robot.y); %Animate set(l,'XData',obj.landmarks.apparentPositions(:,1),'YData',obj.landmarks.apparentPositions(:,2)); rectangle('Position',[-2,-2,4,4]); drawnow end end end end ----------------- classdef landmarks properties fixedPositions; %# positions in a fixed coordinate system. [ x, y ] mapSize; %Map Size. Value is side of square x; y; heading; headingChange; end properties (Dependent) apparentPositions end methods function obj = createLandmarks(mapSize, numberOfTrees) obj.mapSize = mapSize; obj.fixedPositions = obj.mapSize * rand([numberOfTrees, 2]) .* sign(rand([numberOfTrees, 2]) - 0.5); end function apparent = get.apparentPositions(obj) %-STILL ROTATES AROUND ORIGINAL ORIGIN currentPosition = [obj.x ; obj.y]; apparent = bsxfun(@minus,(obj.fixedPositions)',currentPosition)'; apparent = ([cosd(obj.heading) -sind(obj.heading) ; sind(obj.heading) cosd(obj.heading)] * (apparent)')'; end function updatePerspective(obj,tempHeading,tempX,tempY) obj.heading = tempHeading; obj.x = tempX; obj.y = tempY; end end end ----------------- classdef robot properties x y heading velocity end methods function obj = robot(x,y,heading,velocity) obj.x = x; obj.y = y; obj.heading = heading; obj.velocity = velocity; end function updatePosition(obj,headingChange) obj.heading = obj.heading + headingChange; tempy = cosd(obj.heading); tempx = sind(obj.heading); obj.x = obj.x + (tempx*obj.velocity); obj.y = obj.y + (tempy*obj.velocity); end end end The navigate function is the same... I would appreciate any help as to why things aren't working. All I did was take the code from the first section from under comment: %Simulation Loop THIS WAS ORGANIZED and break it into 2 functions. One in robot and one in landmarks. Is a new instance created every time because it's constantly printing the same heading for this line int he robot class obj.heading = obj.heading + headingChange;

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  • How do I implement AABB ray cast hit checking for opengl es on the iPhone

    - by Big Fizzy
    Basically, I draw a 3D cube, I can spin it around but I want to be able to touch it and know where on my cube's surface the user touched. I'm using for setting up, generating and spinning. Its based on the Molecules code and NeHe tutorial #5. Any help, links, tutorials and code would be greatly appreciated. I have lots of development experience but nothing much in the way of openGL and 3d. // // GLViewController.h // NeHe Lesson 05 // // Created by Jeff LaMarche on 12/12/08. // Copyright Jeff LaMarche Consulting 2008. All rights reserved. // #import "GLViewController.h" #import "GLView.h" @implementation GLViewController - (void)drawBox { static const GLfloat cubeVertices[] = { -1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f,-1.0f, 1.0f, -1.0f,-1.0f, 1.0f, -1.0f, 1.0f,-1.0f, 1.0f, 1.0f,-1.0f, 1.0f,-1.0f,-1.0f, -1.0f,-1.0f,-1.0f }; static const GLubyte cubeNumberOfIndices = 36; const GLubyte cubeVertexFaces[] = { 0, 1, 5, // Half of top face 0, 5, 4, // Other half of top face 4, 6, 5, // Half of front face 4, 6, 7, // Other half of front face 0, 1, 2, // Half of back face 0, 3, 2, // Other half of back face 1, 2, 5, // Half of right face 2, 5, 6, // Other half of right face 0, 3, 4, // Half of left face 7, 4, 3, // Other half of left face 3, 6, 2, // Half of bottom face 6, 7, 3, // Other half of bottom face }; const GLubyte cubeFaceColors[] = { 0, 255, 0, 255, 255, 125, 0, 255, 255, 0, 0, 255, 255, 255, 0, 255, 0, 0, 255, 255, 255, 0, 255, 255 }; glEnableClientState(GL_VERTEX_ARRAY); glVertexPointer(3, GL_FLOAT, 0, cubeVertices); int colorIndex = 0; for(int i = 0; i < cubeNumberOfIndices; i += 3) { glColor4ub(cubeFaceColors[colorIndex], cubeFaceColors[colorIndex+1], cubeFaceColors[colorIndex+2], cubeFaceColors[colorIndex+3]); int face = (i / 3.0); if (face%2 != 0.0) colorIndex+=4; glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_BYTE, &cubeVertexFaces[i]); } glDisableClientState(GL_VERTEX_ARRAY); } //move this to a data model later! - (GLfixed)floatToFixed:(GLfloat)aValue; { return (GLfixed) (aValue * 65536.0f); } - (void)drawViewByRotatingAroundX:(float)xRotation rotatingAroundY:(float)yRotation scaling:(float)scaleFactor translationInX:(float)xTranslation translationInY:(float)yTranslation view:(GLView*)view; { glMatrixMode(GL_MODELVIEW); GLfixed currentModelViewMatrix[16] = { 45146, 47441, 2485, 0, -25149, 26775,-54274, 0, -40303, 36435, 36650, 0, 0, 0, 0, 65536 }; /* GLfixed currentModelViewMatrix[16] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 65536 }; */ //glLoadIdentity(); //glOrthof(-1.0f, 1.0f, -1.5f, 1.5f, -10.0f, 4.0f); // Reset rotation system if (isFirstDrawing) { //glLoadIdentity(); glMultMatrixx(currentModelViewMatrix); [self configureLighting]; isFirstDrawing = NO; } // Scale the view to fit current multitouch scaling GLfixed fixedPointScaleFactor = [self floatToFixed:scaleFactor]; glScalex(fixedPointScaleFactor, fixedPointScaleFactor, fixedPointScaleFactor); // Perform incremental rotation based on current angles in X and Y glGetFixedv(GL_MODELVIEW_MATRIX, currentModelViewMatrix); GLfloat totalRotation = sqrt(xRotation*xRotation + yRotation*yRotation); glRotatex([self floatToFixed:totalRotation], (GLfixed)((xRotation/totalRotation) * (GLfloat)currentModelViewMatrix[1] + (yRotation/totalRotation) * (GLfloat)currentModelViewMatrix[0]), (GLfixed)((xRotation/totalRotation) * (GLfloat)currentModelViewMatrix[5] + (yRotation/totalRotation) * (GLfloat)currentModelViewMatrix[4]), (GLfixed)((xRotation/totalRotation) * (GLfloat)currentModelViewMatrix[9] + (yRotation/totalRotation) * (GLfloat)currentModelViewMatrix[8]) ); // Translate the model by the accumulated amount glGetFixedv(GL_MODELVIEW_MATRIX, currentModelViewMatrix); float currentScaleFactor = sqrt(pow((GLfloat)currentModelViewMatrix[0] / 65536.0f, 2.0f) + pow((GLfloat)currentModelViewMatrix[1] / 65536.0f, 2.0f) + pow((GLfloat)currentModelViewMatrix[2] / 65536.0f, 2.0f)); xTranslation = xTranslation / (currentScaleFactor * currentScaleFactor); yTranslation = yTranslation / (currentScaleFactor * currentScaleFactor); // Grab the current model matrix, and use the (0,4,8) components to figure the eye's X axis in the model coordinate system, translate along that glTranslatef(xTranslation * (GLfloat)currentModelViewMatrix[0] / 65536.0f, xTranslation * (GLfloat)currentModelViewMatrix[4] / 65536.0f, xTranslation * (GLfloat)currentModelViewMatrix[8] / 65536.0f); // Grab the current model matrix, and use the (1,5,9) components to figure the eye's Y axis in the model coordinate system, translate along that glTranslatef(yTranslation * (GLfloat)currentModelViewMatrix[1] / 65536.0f, yTranslation * (GLfloat)currentModelViewMatrix[5] / 65536.0f, yTranslation * (GLfloat)currentModelViewMatrix[9] / 65536.0f); // Black background, with depth buffer enabled glClearColor(0.0f, 0.0f, 0.0f, 1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); [self drawBox]; } - (void)configureLighting; { const GLfixed lightAmbient[] = {13107, 13107, 13107, 65535}; const GLfixed lightDiffuse[] = {65535, 65535, 65535, 65535}; const GLfixed matAmbient[] = {65535, 65535, 65535, 65535}; const GLfixed matDiffuse[] = {65535, 65535, 65535, 65535}; const GLfixed lightPosition[] = {30535, -30535, 0, 0}; const GLfixed lightShininess = 20; glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glEnable(GL_COLOR_MATERIAL); glMaterialxv(GL_FRONT_AND_BACK, GL_AMBIENT, matAmbient); glMaterialxv(GL_FRONT_AND_BACK, GL_DIFFUSE, matDiffuse); glMaterialx(GL_FRONT_AND_BACK, GL_SHININESS, lightShininess); glLightxv(GL_LIGHT0, GL_AMBIENT, lightAmbient); glLightxv(GL_LIGHT0, GL_DIFFUSE, lightDiffuse); glLightxv(GL_LIGHT0, GL_POSITION, lightPosition); glEnable(GL_DEPTH_TEST); glShadeModel(GL_SMOOTH); glEnable(GL_NORMALIZE); } -(void)setupView:(GLView*)view { const GLfloat zNear = 0.1, zFar = 1000.0, fieldOfView = 60.0; GLfloat size; glMatrixMode(GL_PROJECTION); glEnable(GL_DEPTH_TEST); size = zNear * tanf(DEGREES_TO_RADIANS(fieldOfView) / 2.0); CGRect rect = view.bounds; glFrustumf(-size, size, -size / (rect.size.width / rect.size.height), size / (rect.size.width / rect.size.height), zNear, zFar); glViewport(0, 0, rect.size.width, rect.size.height); glScissor(0, 0, rect.size.width, rect.size.height); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glClearColor(0.0f, 0.0f, 0.0f, 1.0f); glTranslatef(0.0f, 0.0f, -6.0f); isFirstDrawing = YES; } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; } - (void)dealloc { [super dealloc]; } @end

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  • Using Flot's Bar Graph in an Android WebView with Highlighting

    - by Nicholi
    The issue is unhighlighting bars which are no longer selected in a bar graph plotted by flot in a WebView on Android. Got no other issues drawing the actual graphs (which look beautiful for something so simple btw). I am not extremely knowledgeable in terms of javascript and web design/development but it seems little should have been needed, if it would just work!! :( I believe I'm following the Flot API correctly, if not someone please scream and yell at me. It seems to work just fine in a non-mobile browser at least. Hoping someone has done this before, but if not I've got the minimal necessary code to poke at your droids if inquiring minds would like to test. I've tested on two Nexus Ones (both 2.2.1), and have tried targeting with Andriod 1.5 and 2.2 SDKs (my intention is to target 1.5 if possible). I've been attempting to hack away at this for far too long on my own now. What happens: 1. Graph loads fine with bars. All bars unhighlighted. 2. Select a bar in graph, gets highlighted fine (and a tooltip is placed). 3. Select a different bar in graph, old bar is unhighlighted, old tooltip removed, new bar highlighted and tooltip placed (still no problems). 4. Click in the vast darkness of the graph which should then unhighlight the last bar... but it doesn't. I've tried disabling flot's autohighlight and manually doing it as well to no avail. Looking into flot itself and only getting down to drawOverlay() where the issue seems to begin... An even more disturbing bug(?) appears if the fill bar option is enabled in the graph, but I'd rather just forget about that for now. Also grabbed the latest version of flot from their svn (r290), but made no different from last public release (v0.6). As a complete guess I'm thinking it's an issue with WebKit's javascript implementation (or something specific to Nexus Ones, which wouldn't be so bad), but if there is any ugly hack to just get it to work I'm all ears. I've thrown the graph data directly into the html/js, rather than deal with showing all the code involved in the Java-javascript handler and callbacks. The simple html placed in 'assets/flot/test/' with jquery.js and jquery.flot.js: <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <script src="jquery.js"></script> <script src="jquery.flot.js"></script> <script id="source" language="javascript" type="text/javascript"> var lastItem = null; var plot = null; $(document).ready(function () { //window.testhandler.loadGraph(); // bind plotclick here $("#graphHolder").bind("plotclick", function (event, pos, item) { if (item) { var lastPoint = null; if (lastItem != null) lastPoint = lastItem.datapoint; if (!pointEquals(lastPoint, item.datapoint)) { //if (lastItem != null) // plot.unhighlight(lastItem.series, lastItem.datapoint); lastItem = item; $("#tooltip").remove(); //plot.highlight(item.series, item.datapoint); showTooltip(item.pageX, item.pageY, item.datapoint[1]); } } else if (lastItem != null) { plot.unhighlight(lastItem.series, lastItem.datapoint); // not unhighlighting anything //plot.unhighlight(); // doesn't work either, supposed to unhighlight everything lastItem = null; $("#tooltip").remove(); } }); GotGraph(); }); /** * Show a tooltip above bar in graph * @param {int} x Left coordinate of div * @param {int} y Top coordinate of div * @param {String} contents text to place in div */ function showTooltip(x, y, contents) { $('<div id="tooltip">' + contents + '</div>').css( { position: 'absolute', display: 'none', top: y, left: x, border: '1px solid #fdd', padding: '2px', 'background-color': '#fee', opacity: 0.80 }).appendTo("body").fadeIn(200); } /** * Draw the graph. This is a callback which will be called by Java * * @param {Object} seriesData * @param {Object} seriesOptions */ function GotGraph() { //seriesData, seriesOptions) { var seriesData = [{ "bars":{"lineWidth":2,"show":true,"barWidth":86400000,"align":"center","fill":false}, "data":[[1288569600000,10],[1288656000000,5],[1288742400000,12],[1288828800000,20],[1288915200000,14],[1289001600000,3],[1289174400000,22],[1289260800000,20],[1289347200000,10],[1289433600000,5],[1289520000000,12],[1289606400000,20],[1289692800000,14],[1289779200000,35]]}]; var seriesOptions = { "xaxis":{"twelveHourClock":false,"minTickSize":[1,"day"],"tickSize":[1,"day"],"timeformat":"%d","mode":"time"}, "yaxis":{"min":0}, "grid":{"clickable":true,"autoHighlight":true,"hoverable":false}}; plot = $.plot($("#graphHolder"), seriesData, seriesOptions); } function pointEquals(point1, point2) { if (point1 != null && point2 != null && typeof(point1) == typeof(point2) && point1.length == point2.length) { var i; for (i=0;i<point1.length;i++) { if (point1[i] != point2[i]) { return false; } } return true; } return false; } </script> </head> <body> <div id="graphHolder" STYLE="height:200px;width:400px"></div> </body> </html> The minimal amount of code necessary in onCreate in startup activity: @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); WebView mytestView = new WebView(this); mytestView.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT)); setContentView(mytestView); mytestView.setBackgroundColor(0); mytestView.getSettings().setJavaScriptEnabled(true); mytestView.setClickable(true); mytestView.setFocusable(false); mytestView.setFocusableInTouchMode(false); mytestView.loadUrl("file:///android_asset/flot/test/stats_graph.html"); }

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  • Problem rendering VBO

    - by Onno
    I'm developing a game engine using OpenTK. I'm trying to get to grips with the use of VBO's. I've run into some trouble because somehow it doesn't render correctly. Thus far I've used immediate mode to render a test object, a test cube with a texture. namespace SharpEngine.Utility.Mesh { using System; using System.Collections.Generic; using OpenTK; using OpenTK.Graphics; using OpenTK.Graphics.OpenGL; using SharpEngine.Utility; using System.Drawing; public class ImmediateFaceBasedCube : IMesh { private IList<Face> faces = new List<Face>(); public ImmediateFaceBasedCube() { IList<Vector3> allVertices = new List<Vector3>(); //rechtsbovenvoor allVertices.Add(new Vector3(1.0f, 1.0f, 1.0f)); //0 //rechtsbovenachter allVertices.Add(new Vector3(1.0f, 1.0f, -1.0f)); //1 //linksbovenachter allVertices.Add(new Vector3(-1.0f, 1.0f, -1.0f)); //2 //linksbovenvoor allVertices.Add(new Vector3(-1.0f, 1.0f, 1.0f)); //3 //rechtsondervoor allVertices.Add(new Vector3(1.0f, -1.0f, 1.0f)); //4 //rechtsonderachter allVertices.Add(new Vector3(1.0f, -1.0f, -1.0f)); //5 //linksonderachter allVertices.Add(new Vector3(-1.0f, -1.0f, -1.0f)); //6 //linksondervoor allVertices.Add(new Vector3(-1.0f, -1.0f, 1.0f)); //7 IList<Vector2> textureCoordinates = new List<Vector2>(); textureCoordinates.Add(new Vector2(0, 0)); //AA - 0 textureCoordinates.Add(new Vector2(0, 0.3333333f)); //AB - 1 textureCoordinates.Add(new Vector2(0, 0.6666666f)); //AC - 2 textureCoordinates.Add(new Vector2(0, 1)); //AD - 3 textureCoordinates.Add(new Vector2(0.3333333f, 0)); //BA - 4 textureCoordinates.Add(new Vector2(0.3333333f, 0.3333333f)); //BB - 5 textureCoordinates.Add(new Vector2(0.3333333f, 0.6666666f)); //BC - 6 textureCoordinates.Add(new Vector2(0.3333333f, 1)); //BD - 7 textureCoordinates.Add(new Vector2(0.6666666f, 0)); //CA - 8 textureCoordinates.Add(new Vector2(0.6666666f, 0.3333333f)); //CB - 9 textureCoordinates.Add(new Vector2(0.6666666f, 0.6666666f)); //CC -10 textureCoordinates.Add(new Vector2(0.6666666f, 1)); //CD -11 textureCoordinates.Add(new Vector2(1, 0)); //DA -12 textureCoordinates.Add(new Vector2(1, 0.3333333f)); //DB -13 textureCoordinates.Add(new Vector2(1, 0.6666666f)); //DC -14 textureCoordinates.Add(new Vector2(1, 1)); //DD -15 Vector3 copy1 = new Vector3(-2.0f, -2.5f, -3.5f); IList<Vector3> normals = new List<Vector3>(); normals.Add(new Vector3(0, 1.0f, 0)); //0 normals.Add(new Vector3(0, 0, 1.0f)); //1 normals.Add(new Vector3(1.0f, 0, 0)); //2 normals.Add(new Vector3(0, 0, -1.0f)); //3 normals.Add(new Vector3(-1.0f, 0, 0)); //4 normals.Add(new Vector3(0, -1.0f, 0)); //5 //todo: move vertex normal and texture data to datastructure //todo: VBO based rendering //top face //1 IList<VertexData> verticesT1 = new List<VertexData>(); VertexData T1a = new VertexData(); T1a.Normal = normals[0]; T1a.TexCoord = textureCoordinates[5]; T1a.Position = allVertices[3]; verticesT1.Add(T1a); VertexData T1b = new VertexData(); T1b.Normal = normals[0]; T1b.TexCoord = textureCoordinates[9]; T1b.Position = allVertices[0]; verticesT1.Add(T1b); VertexData T1c = new VertexData(); T1c.Normal = normals[0]; T1c.TexCoord = textureCoordinates[10]; T1c.Position = allVertices[1]; verticesT1.Add(T1c); Face F1 = new Face(verticesT1); faces.Add(F1); //2 IList<VertexData> verticesT2 = new List<VertexData>(); VertexData T2a = new VertexData(); T2a.Normal = normals[0]; T2a.TexCoord = textureCoordinates[10]; T2a.Position = allVertices[1]; verticesT2.Add(T2a); VertexData T2b = new VertexData(); T2b.Normal = normals[0]; T2b.TexCoord = textureCoordinates[6]; T2b.Position = allVertices[2]; verticesT2.Add(T2b); VertexData T2c = new VertexData(); T2c.Normal = normals[0]; T2c.TexCoord = textureCoordinates[5]; T2c.Position = allVertices[3]; verticesT2.Add(T2c); Face F2 = new Face(verticesT2); faces.Add(F2); //front face //3 IList<VertexData> verticesT3 = new List<VertexData>(); VertexData T3a = new VertexData(); T3a.Normal = normals[1]; T3a.TexCoord = textureCoordinates[1]; T3a.Position = allVertices[3]; verticesT3.Add(T3a); VertexData T3b = new VertexData(); T3b.Normal = normals[1]; T3b.TexCoord = textureCoordinates[0]; T3b.Position = allVertices[7]; verticesT3.Add(T3b); VertexData T3c = new VertexData(); T3c.Normal = normals[1]; T3c.TexCoord = textureCoordinates[5]; T3c.Position = allVertices[0]; verticesT3.Add(T3c); Face F3 = new Face(verticesT3); faces.Add(F3); //4 IList<VertexData> verticesT4 = new List<VertexData>(); VertexData T4a = new VertexData(); T4a.Normal = normals[1]; T4a.TexCoord = textureCoordinates[5]; T4a.Position = allVertices[0]; verticesT4.Add(T4a); VertexData T4b = new VertexData(); T4b.Normal = normals[1]; T4b.TexCoord = textureCoordinates[0]; T4b.Position = allVertices[7]; verticesT4.Add(T4b); VertexData T4c = new VertexData(); T4c.Normal = normals[1]; T4c.TexCoord = textureCoordinates[4]; T4c.Position = allVertices[4]; verticesT4.Add(T4c); Face F4 = new Face(verticesT4); faces.Add(F4); //right face //5 IList<VertexData> verticesT5 = new List<VertexData>(); VertexData T5a = new VertexData(); T5a.Normal = normals[2]; T5a.TexCoord = textureCoordinates[2]; T5a.Position = allVertices[0]; verticesT5.Add(T5a); VertexData T5b = new VertexData(); T5b.Normal = normals[2]; T5b.TexCoord = textureCoordinates[1]; T5b.Position = allVertices[4]; verticesT5.Add(T5b); VertexData T5c = new VertexData(); T5c.Normal = normals[2]; T5c.TexCoord = textureCoordinates[6]; T5c.Position = allVertices[1]; verticesT5.Add(T5c); Face F5 = new Face(verticesT5); faces.Add(F5); //6 IList<VertexData> verticesT6 = new List<VertexData>(); VertexData T6a = new VertexData(); T6a.Normal = normals[2]; T6a.TexCoord = textureCoordinates[1]; T6a.Position = allVertices[4]; verticesT6.Add(T6a); VertexData T6b = new VertexData(); T6b.Normal = normals[2]; T6b.TexCoord = textureCoordinates[5]; T6b.Position = allVertices[5]; verticesT6.Add(T6b); VertexData T6c = new VertexData(); T6c.Normal = normals[2]; T6c.TexCoord = textureCoordinates[6]; T6c.Position = allVertices[1]; verticesT6.Add(T6c); Face F6 = new Face(verticesT6); faces.Add(F6); //back face //7 IList<VertexData> verticesT7 = new List<VertexData>(); VertexData T7a = new VertexData(); T7a.Normal = normals[3]; T7a.TexCoord = textureCoordinates[4]; T7a.Position = allVertices[5]; verticesT7.Add(T7a); VertexData T7b = new VertexData(); T7b.Normal = normals[3]; T7b.TexCoord = textureCoordinates[9]; T7b.Position = allVertices[2]; verticesT7.Add(T7b); VertexData T7c = new VertexData(); T7c.Normal = normals[3]; T7c.TexCoord = textureCoordinates[5]; T7c.Position = allVertices[1]; verticesT7.Add(T7c); Face F7 = new Face(verticesT7); faces.Add(F7); //8 IList<VertexData> verticesT8 = new List<VertexData>(); VertexData T8a = new VertexData(); T8a.Normal = normals[3]; T8a.TexCoord = textureCoordinates[9]; T8a.Position = allVertices[2]; verticesT8.Add(T8a); VertexData T8b = new VertexData(); T8b.Normal = normals[3]; T8b.TexCoord = textureCoordinates[4]; T8b.Position = allVertices[5]; verticesT8.Add(T8b); VertexData T8c = new VertexData(); T8c.Normal = normals[3]; T8c.TexCoord = textureCoordinates[8]; T8c.Position = allVertices[6]; verticesT8.Add(T8c); Face F8 = new Face(verticesT8); faces.Add(F8); //left face //9 IList<VertexData> verticesT9 = new List<VertexData>(); VertexData T9a = new VertexData(); T9a.Normal = normals[4]; T9a.TexCoord = textureCoordinates[8]; T9a.Position = allVertices[6]; verticesT9.Add(T9a); VertexData T9b = new VertexData(); T9b.Normal = normals[4]; T9b.TexCoord = textureCoordinates[13]; T9b.Position = allVertices[3]; verticesT9.Add(T9b); VertexData T9c = new VertexData(); T9c.Normal = normals[4]; T9c.TexCoord = textureCoordinates[9]; T9c.Position = allVertices[2]; verticesT9.Add(T9c); Face F9 = new Face(verticesT9); faces.Add(F9); //10 IList<VertexData> verticesT10 = new List<VertexData>(); VertexData T10a = new VertexData(); T10a.Normal = normals[4]; T10a.TexCoord = textureCoordinates[8]; T10a.Position = allVertices[6]; verticesT10.Add(T10a); VertexData T10b = new VertexData(); T10b.Normal = normals[4]; T10b.TexCoord = textureCoordinates[12]; T10b.Position = allVertices[7]; verticesT10.Add(T10b); VertexData T10c = new VertexData(); T10c.Normal = normals[4]; T10c.TexCoord = textureCoordinates[13]; T10c.Position = allVertices[3]; verticesT10.Add(T10c); Face F10 = new Face(verticesT10); faces.Add(F10); //bottom face //11 IList<VertexData> verticesT11 = new List<VertexData>(); VertexData T11a = new VertexData(); T11a.Normal = normals[5]; T11a.TexCoord = textureCoordinates[10]; T11a.Position = allVertices[7]; verticesT11.Add(T11a); VertexData T11b = new VertexData(); T11b.Normal = normals[5]; T11b.TexCoord = textureCoordinates[9]; T11b.Position = allVertices[6]; verticesT11.Add(T11b); VertexData T11c = new VertexData(); T11c.Normal = normals[5]; T11c.TexCoord = textureCoordinates[14]; T11c.Position = allVertices[4]; verticesT11.Add(T11c); Face F11 = new Face(verticesT11); faces.Add(F11); //12 IList<VertexData> verticesT12 = new List<VertexData>(); VertexData T12a = new VertexData(); T12a.Normal = normals[5]; T12a.TexCoord = textureCoordinates[13]; T12a.Position = allVertices[5]; verticesT12.Add(T12a); VertexData T12b = new VertexData(); T12b.Normal = normals[5]; T12b.TexCoord = textureCoordinates[14]; T12b.Position = allVertices[4]; verticesT12.Add(T12b); VertexData T12c = new VertexData(); T12c.Normal = normals[5]; T12c.TexCoord = textureCoordinates[9]; T12c.Position = allVertices[6]; verticesT12.Add(T12c); Face F12 = new Face(verticesT12); faces.Add(F12); } public void draw() { GL.Begin(BeginMode.Triangles); foreach (Face face in faces) { foreach (VertexData datapoint in face.verticesWithTexCoords) { GL.Normal3(datapoint.Normal); GL.TexCoord2(datapoint.TexCoord); GL.Vertex3(datapoint.Position); } } GL.End(); } } } Gets me this very nice picture: The immediate mode cube renders nicely and taught me a bit on how to use OpenGL, but VBO's are the way to go. Since I read on the OpenTK forums that OpenTK has problems doing VA's or DL's, I decided to skip using those. Now, I've tried to change this cube to a VBO by using the same vertex, normal and tc collections, and making float arrays from them by using the coordinates in combination with uint arrays which contain the index numbers from the immediate cube. (see the private functions at end of the code sample) Somehow this only renders two triangles namespace SharpEngine.Utility.Mesh { using System; using System.Collections.Generic; using OpenTK; using OpenTK.Graphics; using OpenTK.Graphics.OpenGL; using SharpEngine.Utility; using System.Drawing; public class VBOFaceBasedCube : IMesh { private int VerticesVBOID; private int VerticesVBOStride; private int VertexCount; private int ELementBufferObjectID; private int textureCoordinateVBOID; private int textureCoordinateVBOStride; //private int textureCoordinateArraySize; private int normalVBOID; private int normalVBOStride; public VBOFaceBasedCube() { IList<Vector3> allVertices = new List<Vector3>(); //rechtsbovenvoor allVertices.Add(new Vector3(1.0f, 1.0f, 1.0f)); //0 //rechtsbovenachter allVertices.Add(new Vector3(1.0f, 1.0f, -1.0f)); //1 //linksbovenachter allVertices.Add(new Vector3(-1.0f, 1.0f, -1.0f)); //2 //linksbovenvoor allVertices.Add(new Vector3(-1.0f, 1.0f, 1.0f)); //3 //rechtsondervoor allVertices.Add(new Vector3(1.0f, -1.0f, 1.0f)); //4 //rechtsonderachter allVertices.Add(new Vector3(1.0f, -1.0f, -1.0f)); //5 //linksonderachter allVertices.Add(new Vector3(-1.0f, -1.0f, -1.0f)); //6 //linksondervoor allVertices.Add(new Vector3(-1.0f, -1.0f, 1.0f)); //7 IList<Vector2> textureCoordinates = new List<Vector2>(); textureCoordinates.Add(new Vector2(0, 0)); //AA - 0 textureCoordinates.Add(new Vector2(0, 0.3333333f)); //AB - 1 textureCoordinates.Add(new Vector2(0, 0.6666666f)); //AC - 2 textureCoordinates.Add(new Vector2(0, 1)); //AD - 3 textureCoordinates.Add(new Vector2(0.3333333f, 0)); //BA - 4 textureCoordinates.Add(new Vector2(0.3333333f, 0.3333333f)); //BB - 5 textureCoordinates.Add(new Vector2(0.3333333f, 0.6666666f)); //BC - 6 textureCoordinates.Add(new Vector2(0.3333333f, 1)); //BD - 7 textureCoordinates.Add(new Vector2(0.6666666f, 0)); //CA - 8 textureCoordinates.Add(new Vector2(0.6666666f, 0.3333333f)); //CB - 9 textureCoordinates.Add(new Vector2(0.6666666f, 0.6666666f)); //CC -10 textureCoordinates.Add(new Vector2(0.6666666f, 1)); //CD -11 textureCoordinates.Add(new Vector2(1, 0)); //DA -12 textureCoordinates.Add(new Vector2(1, 0.3333333f)); //DB -13 textureCoordinates.Add(new Vector2(1, 0.6666666f)); //DC -14 textureCoordinates.Add(new Vector2(1, 1)); //DD -15 Vector3 copy1 = new Vector3(-2.0f, -2.5f, -3.5f); IList<Vector3> normals = new List<Vector3>(); normals.Add(new Vector3(0, 1.0f, 0)); //0 normals.Add(new Vector3(0, 0, 1.0f)); //1 normals.Add(new Vector3(1.0f, 0, 0)); //2 normals.Add(new Vector3(0, 0, -1.0f)); //3 normals.Add(new Vector3(-1.0f, 0, 0)); //4 normals.Add(new Vector3(0, -1.0f, 0)); //5 //todo: VBO based rendering uint[] vertexElements = { 3,0,1, //01 1,2,3, //02 3,7,0, //03 0,7,4, //04 0,4,1, //05 4,5,1, //06 5,2,1, //07 2,5,6, //08 6,3,2, //09 6,7,5, //10 7,6,4, //11 5,4,6 //12 }; VertexCount = vertexElements.Length; IList<uint> vertexElementList = new List<uint>(vertexElements); uint[] normalElements = { 0,0,0, 0,0,0, 1,1,1, 1,1,1, 2,2,2, 2,2,2, 3,3,3, 3,3,3, 4,4,4, 4,4,4, 5,5,5, 5,5,5 }; IList<uint> normalElementList = new List<uint>(normalElements); uint[] textureIndexArray = { 5,9,10, 10,6,5, 1,0,5, 5,0,4, 2,1,6, 1,5,6, 4,9,5, 9,4,8, 8,13,9, 8,12,13, 10,9,14, 13,14,9 }; //textureCoordinateArraySize = textureIndexArray.Length; IList<uint> textureIndexList = new List<uint>(textureIndexArray); LoadVBO(allVertices, normals, textureCoordinates, vertexElements, normalElementList, textureIndexList); } public void draw() { //bind vertices //bind elements //bind normals //bind texture coordinates GL.EnableClientState(ArrayCap.VertexArray); GL.EnableClientState(ArrayCap.NormalArray); GL.EnableClientState(ArrayCap.TextureCoordArray); GL.BindBuffer(BufferTarget.ArrayBuffer, VerticesVBOID); GL.VertexPointer(3, VertexPointerType.Float, VerticesVBOStride, 0); GL.BindBuffer(BufferTarget.ArrayBuffer, normalVBOID); GL.NormalPointer(NormalPointerType.Float, normalVBOStride, 0); GL.BindBuffer(BufferTarget.ArrayBuffer, textureCoordinateVBOID); GL.TexCoordPointer(2, TexCoordPointerType.Float, textureCoordinateVBOStride, 0); GL.BindBuffer(BufferTarget.ElementArrayBuffer, ELementBufferObjectID); GL.DrawElements(BeginMode.Polygon, VertexCount, DrawElementsType.UnsignedShort, 0); } //loads a static VBO void LoadVBO(IList<Vector3> vertices, IList<Vector3> normals, IList<Vector2> texcoords, uint[] elements, IList<uint> normalIndices, IList<uint> texCoordIndices) { int size; //todo // To create a VBO: // 1) Generate the buffer handles for the vertex and element buffers. // 2) Bind the vertex buffer handle and upload your vertex data. Check that the buffer was uploaded correctly. // 3) Bind the element buffer handle and upload your element data. Check that the buffer was uploaded correctly. float[] verticesArray = convertVector3fListToFloatArray(vertices); float[] normalsArray = createFloatArrayFromListOfVector3ElementsAndIndices(normals, normalIndices); float[] textureCoordinateArray = createFloatArrayFromListOfVector2ElementsAndIndices(texcoords, texCoordIndices); GL.GenBuffers(1, out VerticesVBOID); GL.BindBuffer(BufferTarget.ArrayBuffer, VerticesVBOID); Console.WriteLine("load 1 - vertices"); VerticesVBOStride = BlittableValueType.StrideOf(verticesArray); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(verticesArray.Length * sizeof(float)), verticesArray, BufferUsageHint.StaticDraw); GL.GetBufferParameter(BufferTarget.ArrayBuffer, BufferParameterName.BufferSize, out size); if (verticesArray.Length * BlittableValueType.StrideOf(verticesArray) != size) { throw new ApplicationException("Vertex data not uploaded correctly"); } else { Console.WriteLine("load 1 finished ok"); size = 0; } Console.WriteLine("load 2 - elements"); GL.GenBuffers(1, out ELementBufferObjectID); GL.BindBuffer(BufferTarget.ElementArrayBuffer, ELementBufferObjectID); GL.BufferData(BufferTarget.ElementArrayBuffer, (IntPtr)(elements.Length * sizeof(uint)), elements, BufferUsageHint.StaticDraw); GL.GetBufferParameter(BufferTarget.ElementArrayBuffer, BufferParameterName.BufferSize, out size); if (elements.Length * sizeof(uint) != size) { throw new ApplicationException("Element data not uploaded correctly"); } else { size = 0; Console.WriteLine("load 2 finished ok"); } GL.GenBuffers(1, out normalVBOID); GL.BindBuffer(BufferTarget.ArrayBuffer, normalVBOID); Console.WriteLine("load 3 - normals"); normalVBOStride = BlittableValueType.StrideOf(normalsArray); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(normalsArray.Length * sizeof(float)), normalsArray, BufferUsageHint.StaticDraw); GL.GetBufferParameter(BufferTarget.ArrayBuffer, BufferParameterName.BufferSize, out size); Console.WriteLine("load 3 - pre check"); if (normalsArray.Length * BlittableValueType.StrideOf(normalsArray) != size) { throw new ApplicationException("Normal data not uploaded correctly"); } else { Console.WriteLine("load 3 finished ok"); size = 0; } GL.GenBuffers(1, out textureCoordinateVBOID); GL.BindBuffer(BufferTarget.ArrayBuffer, textureCoordinateVBOID); Console.WriteLine("load 4- texture coordinates"); textureCoordinateVBOStride = BlittableValueType.StrideOf(textureCoordinateArray); GL.BufferData(BufferTarget.ArrayBuffer, (IntPtr)(textureCoordinateArray.Length * textureCoordinateVBOStride), textureCoordinateArray, BufferUsageHint.StaticDraw); GL.GetBufferParameter(BufferTarget.ArrayBuffer, BufferParameterName.BufferSize, out size); if (textureCoordinateArray.Length * BlittableValueType.StrideOf(textureCoordinateArray) != size) { throw new ApplicationException("texture coordinate data not uploaded correctly"); } else { Console.WriteLine("load 3 finished ok"); size = 0; } } //used to convert vertex arrayss for use with VBO's private float[] convertVector3fListToFloatArray(IList<Vector3> input) { int arrayElementCount = input.Count * 3; float[] output = new float[arrayElementCount]; int fillCount = 0; foreach (Vector3 v in input) { output[fillCount] = v.X; output[fillCount + 1] = v.Y; output[fillCount + 2] = v.Z; fillCount += 3; } return output; } //used for converting texture coordinate arrays for use with VBO's private float[] convertVector2List_to_floatArray(IList<Vector2> input) { int arrayElementCount = input.Count * 2; float[] output = new float[arrayElementCount]; int fillCount = 0; foreach (Vector2 v in input) { output[fillCount] = v.X; output[fillCount + 1] = v.Y; fillCount += 2; } return output; } //used to create an array of floats from private float[] createFloatArrayFromListOfVector3ElementsAndIndices(IList<Vector3> inputVectors, IList<uint> indices) { int arrayElementCount = inputVectors.Count * indices.Count * 3; float[] output = new float[arrayElementCount]; int fillCount = 0; foreach (int i in indices) { output[fillCount] = inputVectors[i].X; output[fillCount + 1] = inputVectors[i].Y; output[fillCount + 2] = inputVectors[i].Z; fillCount += 3; } return output; } private float[] createFloatArrayFromListOfVector2ElementsAndIndices(IList<Vector2> inputVectors, IList<uint> indices) { int arrayElementCount = inputVectors.Count * indices.Count * 2; float[] output = new float[arrayElementCount]; int fillCount = 0; foreach (int i in indices) { output[fillCount] = inputVectors[i].X; output[fillCount + 1] = inputVectors[i].Y; fillCount += 2; } return output; } } } This code will only render two triangles and they're nothing like I had in mind: I've done some searching. In some other questions I read that, if I did something wrong, I'd get no rendering at all. Clearly, something gets sent to the GFX card, but it might be that I'm not sending the right data. I've tried altering the sequence in which the triangles are rendered by swapping some of the index numbers in the vert, tc and normal index arrays, but this doesn't seem to be of any effect. I'm slightly lost here. What am I doing wrong here?

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  • 256 Windows Azure Worker Roles, Windows Kinect and a 90's Text-Based Ray-Tracer

    - by Alan Smith
    For a couple of years I have been demoing a simple render farm hosted in Windows Azure using worker roles and the Azure Storage service. At the start of the presentation I deploy an Azure application that uses 16 worker roles to render a 1,500 frame 3D ray-traced animation. At the end of the presentation, when the animation was complete, I would play the animation delete the Azure deployment. The standing joke with the audience was that it was that it was a “$2 demo”, as the compute charges for running the 16 instances for an hour was $1.92, factor in the bandwidth charges and it’s a couple of dollars. The point of the demo is that it highlights one of the great benefits of cloud computing, you pay for what you use, and if you need massive compute power for a short period of time using Windows Azure can work out very cost effective. The “$2 demo” was great for presenting at user groups and conferences in that it could be deployed to Azure, used to render an animation, and then removed in a one hour session. I have always had the idea of doing something a bit more impressive with the demo, and scaling it from a “$2 demo” to a “$30 demo”. The challenge was to create a visually appealing animation in high definition format and keep the demo time down to one hour.  This article will take a run through how I achieved this. Ray Tracing Ray tracing, a technique for generating high quality photorealistic images, gained popularity in the 90’s with companies like Pixar creating feature length computer animations, and also the emergence of shareware text-based ray tracers that could run on a home PC. In order to render a ray traced image, the ray of light that would pass from the view point must be tracked until it intersects with an object. At the intersection, the color, reflectiveness, transparency, and refractive index of the object are used to calculate if the ray will be reflected or refracted. Each pixel may require thousands of calculations to determine what color it will be in the rendered image. Pin-Board Toys Having very little artistic talent and a basic understanding of maths I decided to focus on an animation that could be modeled fairly easily and would look visually impressive. I’ve always liked the pin-board desktop toys that become popular in the 80’s and when I was working as a 3D animator back in the 90’s I always had the idea of creating a 3D ray-traced animation of a pin-board, but never found the energy to do it. Even if I had a go at it, the render time to produce an animation that would look respectable on a 486 would have been measured in months. PolyRay Back in 1995 I landed my first real job, after spending three years being a beach-ski-climbing-paragliding-bum, and was employed to create 3D ray-traced animations for a CD-ROM that school kids would use to learn physics. I had got into the strange and wonderful world of text-based ray tracing, and was using a shareware ray-tracer called PolyRay. PolyRay takes a text file describing a scene as input and, after a few hours processing on a 486, produced a high quality ray-traced image. The following is an example of a basic PolyRay scene file. background Midnight_Blue   static define matte surface { ambient 0.1 diffuse 0.7 } define matte_white texture { matte { color white } } define matte_black texture { matte { color dark_slate_gray } } define position_cylindrical 3 define lookup_sawtooth 1 define light_wood <0.6, 0.24, 0.1> define median_wood <0.3, 0.12, 0.03> define dark_wood <0.05, 0.01, 0.005>     define wooden texture { noise surface { ambient 0.2  diffuse 0.7  specular white, 0.5 microfacet Reitz 10 position_fn position_cylindrical position_scale 1  lookup_fn lookup_sawtooth octaves 1 turbulence 1 color_map( [0.0, 0.2, light_wood, light_wood] [0.2, 0.3, light_wood, median_wood] [0.3, 0.4, median_wood, light_wood] [0.4, 0.7, light_wood, light_wood] [0.7, 0.8, light_wood, median_wood] [0.8, 0.9, median_wood, light_wood] [0.9, 1.0, light_wood, dark_wood]) } } define glass texture { surface { ambient 0 diffuse 0 specular 0.2 reflection white, 0.1 transmission white, 1, 1.5 }} define shiny surface { ambient 0.1 diffuse 0.6 specular white, 0.6 microfacet Phong 7  } define steely_blue texture { shiny { color black } } define chrome texture { surface { color white ambient 0.0 diffuse 0.2 specular 0.4 microfacet Phong 10 reflection 0.8 } }   viewpoint {     from <4.000, -1.000, 1.000> at <0.000, 0.000, 0.000> up <0, 1, 0> angle 60     resolution 640, 480 aspect 1.6 image_format 0 }       light <-10, 30, 20> light <-10, 30, -20>   object { disc <0, -2, 0>, <0, 1, 0>, 30 wooden }   object { sphere <0.000, 0.000, 0.000>, 1.00 chrome } object { cylinder <0.000, 0.000, 0.000>, <0.000, 0.000, -4.000>, 0.50 chrome }   After setting up the background and defining colors and textures, the viewpoint is specified. The “camera” is located at a point in 3D space, and it looks towards another point. The angle, image resolution, and aspect ratio are specified. Two lights are present in the image at defined coordinates. The three objects in the image are a wooden disc to represent a table top, and a sphere and cylinder that intersect to form a pin that will be used for the pin board toy in the final animation. When the image is rendered, the following image is produced. The pins are modeled with a chrome surface, so they reflect the environment around them. Note that the scale of the pin shaft is not correct, this will be fixed later. Modeling the Pin Board The frame of the pin-board is made up of three boxes, and six cylinders, the front box is modeled using a clear, slightly reflective solid, with the same refractive index of glass. The other shapes are modeled as metal. object { box <-5.5, -1.5, 1>, <5.5, 5.5, 1.2> glass } object { box <-5.5, -1.5, -0.04>, <5.5, 5.5, -0.09> steely_blue } object { box <-5.5, -1.5, -0.52>, <5.5, 5.5, -0.59> steely_blue } object { cylinder <-5.2, -1.2, 1.4>, <-5.2, -1.2, -0.74>, 0.2 steely_blue } object { cylinder <5.2, -1.2, 1.4>, <5.2, -1.2, -0.74>, 0.2 steely_blue } object { cylinder <-5.2, 5.2, 1.4>, <-5.2, 5.2, -0.74>, 0.2 steely_blue } object { cylinder <5.2, 5.2, 1.4>, <5.2, 5.2, -0.74>, 0.2 steely_blue } object { cylinder <0, -1.2, 1.4>, <0, -1.2, -0.74>, 0.2 steely_blue } object { cylinder <0, 5.2, 1.4>, <0, 5.2, -0.74>, 0.2 steely_blue }   In order to create the matrix of pins that make up the pin board I used a basic console application with a few nested loops to create two intersecting matrixes of pins, which models the layout used in the pin boards. The resulting image is shown below. The pin board contains 11,481 pins, with the scene file containing 23,709 lines of code. For the complete animation 2,000 scene files will be created, which is over 47 million lines of code. Each pin in the pin-board will slide out a specific distance when an object is pressed into the back of the board. This is easily modeled by setting the Z coordinate of the pin to a specific value. In order to set all of the pins in the pin-board to the correct position, a bitmap image can be used. The position of the pin can be set based on the color of the pixel at the appropriate position in the image. When the Windows Azure logo is used to set the Z coordinate of the pins, the following image is generated. The challenge now was to make a cool animation. The Azure Logo is fine, but it is static. Using a normal video to animate the pins would not work; the colors in the video would not be the same as the depth of the objects from the camera. In order to simulate the pin board accurately a series of frames from a depth camera could be used. Windows Kinect The Kenect controllers for the X-Box 360 and Windows feature a depth camera. The Kinect SDK for Windows provides a programming interface for Kenect, providing easy access for .NET developers to the Kinect sensors. The Kinect Explorer provided with the Kinect SDK is a great starting point for exploring Kinect from a developers perspective. Both the X-Box 360 Kinect and the Windows Kinect will work with the Kinect SDK, the Windows Kinect is required for commercial applications, but the X-Box Kinect can be used for hobby projects. The Windows Kinect has the advantage of providing a mode to allow depth capture with objects closer to the camera, which makes for a more accurate depth image for setting the pin positions. Creating a Depth Field Animation The depth field animation used to set the positions of the pin in the pin board was created using a modified version of the Kinect Explorer sample application. In order to simulate the pin board accurately, a small section of the depth range from the depth sensor will be used. Any part of the object in front of the depth range will result in a white pixel; anything behind the depth range will be black. Within the depth range the pixels in the image will be set to RGB values from 0,0,0 to 255,255,255. A screen shot of the modified Kinect Explorer application is shown below. The Kinect Explorer sample application was modified to include slider controls that are used to set the depth range that forms the image from the depth stream. This allows the fine tuning of the depth image that is required for simulating the position of the pins in the pin board. The Kinect Explorer was also modified to record a series of images from the depth camera and save them as a sequence JPEG files that will be used to animate the pins in the animation the Start and Stop buttons are used to start and stop the image recording. En example of one of the depth images is shown below. Once a series of 2,000 depth images has been captured, the task of creating the animation can begin. Rendering a Test Frame In order to test the creation of frames and get an approximation of the time required to render each frame a test frame was rendered on-premise using PolyRay. The output of the rendering process is shown below. The test frame contained 23,629 primitive shapes, most of which are the spheres and cylinders that are used for the 11,800 or so pins in the pin board. The 1280x720 image contains 921,600 pixels, but as anti-aliasing was used the number of rays that were calculated was 4,235,777, with 3,478,754,073 object boundaries checked. The test frame of the pin board with the depth field image applied is shown below. The tracing time for the test frame was 4 minutes 27 seconds, which means rendering the2,000 frames in the animation would take over 148 hours, or a little over 6 days. Although this is much faster that an old 486, waiting almost a week to see the results of an animation would make it challenging for animators to create, view, and refine their animations. It would be much better if the animation could be rendered in less than one hour. Windows Azure Worker Roles The cost of creating an on-premise render farm to render animations increases in proportion to the number of servers. The table below shows the cost of servers for creating a render farm, assuming a cost of $500 per server. Number of Servers Cost 1 $500 16 $8,000 256 $128,000   As well as the cost of the servers, there would be additional costs for networking, racks etc. Hosting an environment of 256 servers on-premise would require a server room with cooling, and some pretty hefty power cabling. The Windows Azure compute services provide worker roles, which are ideal for performing processor intensive compute tasks. With the scalability available in Windows Azure a job that takes 256 hours to complete could be perfumed using different numbers of worker roles. The time and cost of using 1, 16 or 256 worker roles is shown below. Number of Worker Roles Render Time Cost 1 256 hours $30.72 16 16 hours $30.72 256 1 hour $30.72   Using worker roles in Windows Azure provides the same cost for the 256 hour job, irrespective of the number of worker roles used. Provided the compute task can be broken down into many small units, and the worker role compute power can be used effectively, it makes sense to scale the application so that the task is completed quickly, making the results available in a timely fashion. The task of rendering 2,000 frames in an animation is one that can easily be broken down into 2,000 individual pieces, which can be performed by a number of worker roles. Creating a Render Farm in Windows Azure The architecture of the render farm is shown in the following diagram. The render farm is a hybrid application with the following components: ·         On-Premise o   Windows Kinect – Used combined with the Kinect Explorer to create a stream of depth images. o   Animation Creator – This application uses the depth images from the Kinect sensor to create scene description files for PolyRay. These files are then uploaded to the jobs blob container, and job messages added to the jobs queue. o   Process Monitor – This application queries the role instance lifecycle table and displays statistics about the render farm environment and render process. o   Image Downloader – This application polls the image queue and downloads the rendered animation files once they are complete. ·         Windows Azure o   Azure Storage – Queues and blobs are used for the scene description files and completed frames. A table is used to store the statistics about the rendering environment.   The architecture of each worker role is shown below.   The worker role is configured to use local storage, which provides file storage on the worker role instance that can be use by the applications to render the image and transform the format of the image. The service definition for the worker role with the local storage configuration highlighted is shown below. <?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="CloudRay" >   <WorkerRole name="CloudRayWorkerRole" vmsize="Small">     <Imports>     </Imports>     <ConfigurationSettings>       <Setting name="DataConnectionString" />     </ConfigurationSettings>     <LocalResources>       <LocalStorage name="RayFolder" cleanOnRoleRecycle="true" />     </LocalResources>   </WorkerRole> </ServiceDefinition>     The two executable programs, PolyRay.exe and DTA.exe are included in the Azure project, with Copy Always set as the property. PolyRay will take the scene description file and render it to a Truevision TGA file. As the TGA format has not seen much use since the mid 90’s it is converted to a JPG image using Dave's Targa Animator, another shareware application from the 90’s. Each worker roll will use the following process to render the animation frames. 1.       The worker process polls the job queue, if a job is available the scene description file is downloaded from blob storage to local storage. 2.       PolyRay.exe is started in a process with the appropriate command line arguments to render the image as a TGA file. 3.       DTA.exe is started in a process with the appropriate command line arguments convert the TGA file to a JPG file. 4.       The JPG file is uploaded from local storage to the images blob container. 5.       A message is placed on the images queue to indicate a new image is available for download. 6.       The job message is deleted from the job queue. 7.       The role instance lifecycle table is updated with statistics on the number of frames rendered by the worker role instance, and the CPU time used. The code for this is shown below. public override void Run() {     // Set environment variables     string polyRayPath = Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), PolyRayLocation);     string dtaPath = Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), DTALocation);       LocalResource rayStorage = RoleEnvironment.GetLocalResource("RayFolder");     string localStorageRootPath = rayStorage.RootPath;       JobQueue jobQueue = new JobQueue("renderjobs");     JobQueue downloadQueue = new JobQueue("renderimagedownloadjobs");     CloudRayBlob sceneBlob = new CloudRayBlob("scenes");     CloudRayBlob imageBlob = new CloudRayBlob("images");     RoleLifecycleDataSource roleLifecycleDataSource = new RoleLifecycleDataSource();       Frames = 0;       while (true)     {         // Get the render job from the queue         CloudQueueMessage jobMsg = jobQueue.Get();           if (jobMsg != null)         {             // Get the file details             string sceneFile = jobMsg.AsString;             string tgaFile = sceneFile.Replace(".pi", ".tga");             string jpgFile = sceneFile.Replace(".pi", ".jpg");               string sceneFilePath = Path.Combine(localStorageRootPath, sceneFile);             string tgaFilePath = Path.Combine(localStorageRootPath, tgaFile);             string jpgFilePath = Path.Combine(localStorageRootPath, jpgFile);               // Copy the scene file to local storage             sceneBlob.DownloadFile(sceneFilePath);               // Run the ray tracer.             string polyrayArguments =                 string.Format("\"{0}\" -o \"{1}\" -a 2", sceneFilePath, tgaFilePath);             Process polyRayProcess = new Process();             polyRayProcess.StartInfo.FileName =                 Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), polyRayPath);             polyRayProcess.StartInfo.Arguments = polyrayArguments;             polyRayProcess.Start();             polyRayProcess.WaitForExit();               // Convert the image             string dtaArguments =                 string.Format(" {0} /FJ /P{1}", tgaFilePath, Path.GetDirectoryName (jpgFilePath));             Process dtaProcess = new Process();             dtaProcess.StartInfo.FileName =                 Path.Combine(Environment.GetEnvironmentVariable("RoleRoot"), dtaPath);             dtaProcess.StartInfo.Arguments = dtaArguments;             dtaProcess.Start();             dtaProcess.WaitForExit();               // Upload the image to blob storage             imageBlob.UploadFile(jpgFilePath);               // Add a download job.             downloadQueue.Add(jpgFile);               // Delete the render job message             jobQueue.Delete(jobMsg);               Frames++;         }         else         {             Thread.Sleep(1000);         }           // Log the worker role activity.         roleLifecycleDataSource.Alive             ("CloudRayWorker", RoleLifecycleDataSource.RoleLifecycleId, Frames);     } }     Monitoring Worker Role Instance Lifecycle In order to get more accurate statistics about the lifecycle of the worker role instances used to render the animation data was tracked in an Azure storage table. The following class was used to track the worker role lifecycles in Azure storage.   public class RoleLifecycle : TableServiceEntity {     public string ServerName { get; set; }     public string Status { get; set; }     public DateTime StartTime { get; set; }     public DateTime EndTime { get; set; }     public long SecondsRunning { get; set; }     public DateTime LastActiveTime { get; set; }     public int Frames { get; set; }     public string Comment { get; set; }       public RoleLifecycle()     {     }       public RoleLifecycle(string roleName)     {         PartitionKey = roleName;         RowKey = Utils.GetAscendingRowKey();         Status = "Started";         StartTime = DateTime.UtcNow;         LastActiveTime = StartTime;         EndTime = StartTime;         SecondsRunning = 0;         Frames = 0;     } }     A new instance of this class is created and added to the storage table when the role starts. It is then updated each time the worker renders a frame to record the total number of frames rendered and the total processing time. These statistics are used be the monitoring application to determine the effectiveness of use of resources in the render farm. Rendering the Animation The Azure solution was deployed to Windows Azure with the service configuration set to 16 worker role instances. This allows for the application to be tested in the cloud environment, and the performance of the application determined. When I demo the application at conferences and user groups I often start with 16 instances, and then scale up the application to the full 256 instances. The configuration to run 16 instances is shown below. <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="CloudRay" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="1" osVersion="*">   <Role name="CloudRayWorkerRole">     <Instances count="16" />     <ConfigurationSettings>       <Setting name="DataConnectionString"         value="DefaultEndpointsProtocol=https;AccountName=cloudraydata;AccountKey=..." />     </ConfigurationSettings>   </Role> </ServiceConfiguration>     About six minutes after deploying the application the first worker roles become active and start to render the first frames of the animation. The CloudRay Monitor application displays an icon for each worker role instance, with a number indicating the number of frames that the worker role has rendered. The statistics on the left show the number of active worker roles and statistics about the render process. The render time is the time since the first worker role became active; the CPU time is the total amount of processing time used by all worker role instances to render the frames.   Five minutes after the first worker role became active the last of the 16 worker roles activated. By this time the first seven worker roles had each rendered one frame of the animation.   With 16 worker roles u and running it can be seen that one hour and 45 minutes CPU time has been used to render 32 frames with a render time of just under 10 minutes.     At this rate it would take over 10 hours to render the 2,000 frames of the full animation. In order to complete the animation in under an hour more processing power will be required. Scaling the render farm from 16 instances to 256 instances is easy using the new management portal. The slider is set to 256 instances, and the configuration saved. We do not need to re-deploy the application, and the 16 instances that are up and running will not be affected. Alternatively, the configuration file for the Azure service could be modified to specify 256 instances.   <?xml version="1.0" encoding="utf-8"?> <ServiceConfiguration serviceName="CloudRay" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration" osFamily="1" osVersion="*">   <Role name="CloudRayWorkerRole">     <Instances count="256" />     <ConfigurationSettings>       <Setting name="DataConnectionString"         value="DefaultEndpointsProtocol=https;AccountName=cloudraydata;AccountKey=..." />     </ConfigurationSettings>   </Role> </ServiceConfiguration>     Six minutes after the new configuration has been applied 75 new worker roles have activated and are processing their first frames.   Five minutes later the full configuration of 256 worker roles is up and running. We can see that the average rate of frame rendering has increased from 3 to 12 frames per minute, and that over 17 hours of CPU time has been utilized in 23 minutes. In this test the time to provision 140 worker roles was about 11 minutes, which works out at about one every five seconds.   We are now half way through the rendering, with 1,000 frames complete. This has utilized just under three days of CPU time in a little over 35 minutes.   The animation is now complete, with 2,000 frames rendered in a little over 52 minutes. The CPU time used by the 256 worker roles is 6 days, 7 hours and 22 minutes with an average frame rate of 38 frames per minute. The rendering of the last 1,000 frames took 16 minutes 27 seconds, which works out at a rendering rate of 60 frames per minute. The frame counts in the server instances indicate that the use of a queue to distribute the workload has been very effective in distributing the load across the 256 worker role instances. The first 16 instances that were deployed first have rendered between 11 and 13 frames each, whilst the 240 instances that were added when the application was scaled have rendered between 6 and 9 frames each.   Completed Animation I’ve uploaded the completed animation to YouTube, a low resolution preview is shown below. Pin Board Animation Created using Windows Kinect and 256 Windows Azure Worker Roles   The animation can be viewed in 1280x720 resolution at the following link: http://www.youtube.com/watch?v=n5jy6bvSxWc Effective Use of Resources According to the CloudRay monitor statistics the animation took 6 days, 7 hours and 22 minutes CPU to render, this works out at 152 hours of compute time, rounded up to the nearest hour. As the usage for the worker role instances are billed for the full hour, it may have been possible to render the animation using fewer than 256 worker roles. When deciding the optimal usage of resources, the time required to provision and start the worker roles must also be considered. In the demo I started with 16 worker roles, and then scaled the application to 256 worker roles. It would have been more optimal to start the application with maybe 200 worker roles, and utilized the full hour that I was being billed for. This would, however, have prevented showing the ease of scalability of the application. The new management portal displays the CPU usage across the worker roles in the deployment. The average CPU usage across all instances is 93.27%, with over 99% used when all the instances are up and running. This shows that the worker role resources are being used very effectively. Grid Computing Scenarios Although I am using this scenario for a hobby project, there are many scenarios where a large amount of compute power is required for a short period of time. Windows Azure provides a great platform for developing these types of grid computing applications, and can work out very cost effective. ·         Windows Azure can provide massive compute power, on demand, in a matter of minutes. ·         The use of queues to manage the load balancing of jobs between role instances is a simple and effective solution. ·         Using a cloud-computing platform like Windows Azure allows proof-of-concept scenarios to be tested and evaluated on a very low budget. ·         No charges for inbound data transfer makes the uploading of large data sets to Windows Azure Storage services cost effective. (Transaction charges still apply.) Tips for using Windows Azure for Grid Computing Scenarios I found the implementation of a render farm using Windows Azure a fairly simple scenario to implement. I was impressed by ease of scalability that Azure provides, and by the short time that the application took to scale from 16 to 256 worker role instances. In this case it was around 13 minutes, in other tests it took between 10 and 20 minutes. The following tips may be useful when implementing a grid computing project in Windows Azure. ·         Using an Azure Storage queue to load-balance the units of work across multiple worker roles is simple and very effective. The design I have used in this scenario could easily scale to many thousands of worker role instances. ·         Windows Azure accounts are typically limited to 20 cores. If you need to use more than this, a call to support and a credit card check will be required. ·         Be aware of how the billing model works. You will be charged for worker role instances for the full clock our in which the instance is deployed. Schedule the workload to start just after the clock hour has started. ·         Monitor the utilization of the resources you are provisioning, ensure that you are not paying for worker roles that are idle. ·         If you are deploying third party applications to worker roles, you may well run into licensing issues. Purchasing software licenses on a per-processor basis when using hundreds of processors for a short time period would not be cost effective. ·         Third party software may also require installation onto the worker roles, which can be accomplished using start-up tasks. Bear in mind that adding a startup task and possible re-boot will add to the time required for the worker role instance to start and activate. An alternative may be to use a prepared VM and use VM roles. ·         Consider using the Windows Azure Autoscaling Application Block (WASABi) to autoscale the worker roles in your application. When using a large number of worker roles, the utilization must be carefully monitored, if the scaling algorithms are not optimal it could get very expensive!

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  • Building a better mouse-trap &ndash; Improving the creation of XML Message Requests using Reflection, XML &amp; XSLT

    - by paulschapman
    Introduction The way I previously created messages to send to the GovTalk service I used the XMLDocument to create the request. While this worked it left a number of problems; not least that for every message a special function would need to created. This is OK for the short term but the biggest cost in any software project is maintenance and this would be a headache to maintain. So the following is a somewhat better way of achieving the same thing. For the purposes of this article I am going to be using the CompanyNumberSearch request of the GovTalk service – although this technique would work for any service that accepted XML. The C# functions which send and receive the messages remain the same. The magic sauce in this is the XSLT which defines the structure of the request, and the use of objects in conjunction with reflection to provide the content. It is a bit like Sweet Chilli Sauce added to Chicken on a bed of rice. So on to the Sweet Chilli Sauce The Sweet Chilli Sauce The request to search for a company based on it’s number is as follows; <GovTalkMessage xsi:schemaLocation="http://www.govtalk.gov.uk/CM/envelope http://xmlgw.companieshouse.gov.uk/v1-0/schema/Egov_ch-v2-0.xsd" xmlns="http://www.govtalk.gov.uk/CM/envelope" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" > <EnvelopeVersion>1.0</EnvelopeVersion> <Header> <MessageDetails> <Class>NumberSearch</Class> <Qualifier>request</Qualifier> <TransactionID>1</TransactionID> </MessageDetails> <SenderDetails> <IDAuthentication> <SenderID>????????????????????????????????</SenderID> <Authentication> <Method>CHMD5</Method> <Value>????????????????????????????????</Value> </Authentication> </IDAuthentication> </SenderDetails> </Header> <GovTalkDetails> <Keys/> </GovTalkDetails> <Body> <NumberSearchRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://xmlgw.companieshouse.gov.uk/v1-0/schema/NumberSearch.xsd"> <PartialCompanyNumber>99999999</PartialCompanyNumber> <DataSet>LIVE</DataSet> <SearchRows>1</SearchRows> </NumberSearchRequest> </Body> </GovTalkMessage> This is the XML that we send to the GovTalk Service and we get back a list of companies that match the criteria passed A message is structured in two parts; The envelope which identifies the person sending the request, with the name of the request, and the body which gives the detail of the company we are looking for. The Chilli What makes it possible is the use of XSLT to define the message – and serialization to convert each request object into XML. To start we need to create an object which will represent the contents of the message we are sending. However there is a common properties in all the messages that we send to Companies House. These properties are as follows SenderId – the id of the person sending the message SenderPassword – the password associated with Id TransactionId – Unique identifier for the message AuthenticationValue – authenticates the request Because these properties are unique to the Companies House message, and because they are shared with all messages they are perfect candidates for a base class. The class is as follows; using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Security.Cryptography; using System.Text; using System.Text.RegularExpressions; using Microsoft.WindowsAzure.ServiceRuntime; namespace CompanyHub.Services { public class GovTalkRequest { public GovTalkRequest() { try { SenderID = RoleEnvironment.GetConfigurationSettingValue("SenderId"); SenderPassword = RoleEnvironment.GetConfigurationSettingValue("SenderPassword"); TransactionId = DateTime.Now.Ticks.ToString(); AuthenticationValue = EncodePassword(String.Format("{0}{1}{2}", SenderID, SenderPassword, TransactionId)); } catch (System.Exception ex) { throw ex; } } /// <summary> /// returns the Sender ID to be used when communicating with the GovTalk Service /// </summary> public String SenderID { get; set; } /// <summary> /// return the password to be used when communicating with the GovTalk Service /// </summary> public String SenderPassword { get; set; } // end SenderPassword /// <summary> /// Transaction Id - uses the Time and Date converted to Ticks /// </summary> public String TransactionId { get; set; } // end TransactionId /// <summary> /// calculate the authentication value that will be used when /// communicating with /// </summary> public String AuthenticationValue { get; set; } // end AuthenticationValue property /// <summary> /// encodes password(s) using MD5 /// </summary> /// <param name="clearPassword"></param> /// <returns></returns> public static String EncodePassword(String clearPassword) { MD5CryptoServiceProvider md5Hasher = new MD5CryptoServiceProvider(); byte[] hashedBytes; UTF32Encoding encoder = new UTF32Encoding(); hashedBytes = md5Hasher.ComputeHash(ASCIIEncoding.Default.GetBytes(clearPassword)); String result = Regex.Replace(BitConverter.ToString(hashedBytes), "-", "").ToLower(); return result; } } } There is nothing particularly clever here, except for the EncodePassword method which hashes the value made up of the SenderId, Password and Transaction id. Each message inherits from this object. So for the Company Number Search in addition to the properties above we need a partial number, which dataset to search – for the purposes of the project we only need to search the LIVE set so this can be set in the constructor and the SearchRows. Again all are set as properties. With the SearchRows and DataSet initialized in the constructor. public class CompanyNumberSearchRequest : GovTalkRequest, IDisposable { /// <summary> /// /// </summary> public CompanyNumberSearchRequest() : base() { DataSet = "LIVE"; SearchRows = 1; } /// <summary> /// Company Number to search against /// </summary> public String PartialCompanyNumber { get; set; } /// <summary> /// What DataSet should be searched for the company /// </summary> public String DataSet { get; set; } /// <summary> /// How many rows should be returned /// </summary> public int SearchRows { get; set; } public void Dispose() { DataSet = String.Empty; PartialCompanyNumber = String.Empty; DataSet = "LIVE"; SearchRows = 1; } } As well as inheriting from our base class, I have also inherited from IDisposable – not just because it is just plain good practice to dispose of objects when coding, but it gives also gives us more versatility when using the object. There are four stages in making a request and this is reflected in the four methods we execute in making a call to the Companies House service; Create a request Send a request Check the status If OK then get the results of the request I’ve implemented each of these stages within a static class called Toolbox – which also means I don’t need to create an instance of the class to use it. When making a request there are three stages; Get the template for the message Serialize the object representing the message Transform the serialized object using a predefined XSLT file. Each of my templates I have defined as an embedded resource. When retrieving a resource of this kind we have to include the full namespace to the resource. In making the code re-usable as much as possible I defined the full ‘path’ within the GetRequest method. requestFile = String.Format("CompanyHub.Services.Schemas.{0}", RequestFile); So we now have the full path of the file within the assembly. Now all we need do is retrieve the assembly and get the resource. asm = Assembly.GetExecutingAssembly(); sr = asm.GetManifestResourceStream(requestFile); Once retrieved  So this can be returned to the calling function and we now have a stream of XSLT to define the message. Time now to serialize the request to create the other side of this message. // Serialize object containing Request, Load into XML Document t = Obj.GetType(); ms = new MemoryStream(); serializer = new XmlSerializer(t); xmlTextWriter = new XmlTextWriter(ms, Encoding.ASCII); serializer.Serialize(xmlTextWriter, Obj); ms = (MemoryStream)xmlTextWriter.BaseStream; GovTalkRequest = Toolbox.ConvertByteArrayToString(ms.ToArray()); First off we need the type of the object so we make a call to the GetType method of the object containing the Message properties. Next we need a MemoryStream, XmlSerializer and an XMLTextWriter so these can be initialized. The object is serialized by making the call to the Serialize method of the serializer object. The result of that is then converted into a MemoryStream. That MemoryStream is then converted into a string. ConvertByteArrayToString This is a fairly simple function which uses an ASCIIEncoding object found within the System.Text namespace to convert an array of bytes into a string. public static String ConvertByteArrayToString(byte[] bytes) { System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding(); return enc.GetString(bytes); } I only put it into a function because I will be using this in various places. The Sauce When adding support for other messages outside of creating a new object to store the properties of the message, the C# components do not need to change. It is in the XSLT file that the versatility of the technique lies. The XSLT file determines the format of the message. For the CompanyNumberSearch the XSLT file is as follows; <?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:template match="/"> <GovTalkMessage xsi:schemaLocation="http://www.govtalk.gov.uk/CM/envelope http://xmlgw.companieshouse.gov.uk/v1-0/schema/Egov_ch-v2-0.xsd" xmlns="http://www.govtalk.gov.uk/CM/envelope" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" > <EnvelopeVersion>1.0</EnvelopeVersion> <Header> <MessageDetails> <Class>NumberSearch</Class> <Qualifier>request</Qualifier> <TransactionID> <xsl:value-of select="CompanyNumberSearchRequest/TransactionId"/> </TransactionID> </MessageDetails> <SenderDetails> <IDAuthentication> <SenderID><xsl:value-of select="CompanyNumberSearchRequest/SenderID"/></SenderID> <Authentication> <Method>CHMD5</Method> <Value> <xsl:value-of select="CompanyNumberSearchRequest/AuthenticationValue"/> </Value> </Authentication> </IDAuthentication> </SenderDetails> </Header> <GovTalkDetails> <Keys/> </GovTalkDetails> <Body> <NumberSearchRequest xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="http://xmlgw.companieshouse.gov.uk/v1-0/schema/NumberSearch.xsd"> <PartialCompanyNumber> <xsl:value-of select="CompanyNumberSearchRequest/PartialCompanyNumber"/> </PartialCompanyNumber> <DataSet> <xsl:value-of select="CompanyNumberSearchRequest/DataSet"/> </DataSet> <SearchRows> <xsl:value-of select="CompanyNumberSearchRequest/SearchRows"/> </SearchRows> </NumberSearchRequest> </Body> </GovTalkMessage> </xsl:template> </xsl:stylesheet> The outer two tags define that this is a XSLT stylesheet and the root tag from which the nodes are searched for. The GovTalkMessage is the format of the message that will be sent to Companies House. We first set up the XslCompiledTransform object which will transform the XSLT template and the serialized object into the request to Companies House. xslt = new XslCompiledTransform(); resultStream = new MemoryStream(); writer = new XmlTextWriter(resultStream, Encoding.ASCII); doc = new XmlDocument(); The Serialize method require XmlTextWriter to write the XML (writer) and a stream to place the transferred object into (writer). The XML will be loaded into an XMLDocument object (doc) prior to the transformation. // create XSLT Template xslTemplate = Toolbox.GetRequest(Template); xslTemplate.Seek(0, SeekOrigin.Begin); templateReader = XmlReader.Create(xslTemplate); xslt.Load(templateReader); I have stored all the templates as a series of Embedded Resources and the GetRequestCall takes the name of the template and extracts the relevent XSLT file. /// <summary> /// Gets the framwork XML which makes the request /// </summary> /// <param name="RequestFile"></param> /// <returns></returns> public static Stream GetRequest(String RequestFile) { String requestFile = String.Empty; Stream sr = null; Assembly asm = null; try { requestFile = String.Format("CompanyHub.Services.Schemas.{0}", RequestFile); asm = Assembly.GetExecutingAssembly(); sr = asm.GetManifestResourceStream(requestFile); } catch (Exception) { throw; } finally { asm = null; } return sr; } // end private static stream GetRequest We first take the template name and expand it to include the full namespace to the Embedded Resource I like to keep all my schemas in the same directory and so the namespace reflects this. The rest is the default namespace for the project. Then we get the currently executing assembly (which will contain the resources with the call to GetExecutingAssembly() ) Finally we get a stream which contains the XSLT file. We use this stream and then load an XmlReader with the contents of the template, and that is in turn loaded into the XslCompiledTransform object. We convert the object containing the message properties into Xml by serializing it; calling the Serialize() method of the XmlSerializer object. To set up the object we do the following; t = Obj.GetType(); ms = new MemoryStream(); serializer = new XmlSerializer(t); xmlTextWriter = new XmlTextWriter(ms, Encoding.ASCII); We first determine the type of the object being transferred by calling GetType() We create an XmlSerializer object by passing the type of the object being serialized. The serializer writes to a memory stream and that is linked to an XmlTextWriter. Next job is to serialize the object and load it into an XmlDocument. serializer.Serialize(xmlTextWriter, Obj); ms = (MemoryStream)xmlTextWriter.BaseStream; xmlRequest = new XmlTextReader(ms); GovTalkRequest = Toolbox.ConvertByteArrayToString(ms.ToArray()); doc.LoadXml(GovTalkRequest); Time to transform the XML to construct the full request. xslt.Transform(doc, writer); resultStream.Seek(0, SeekOrigin.Begin); request = Toolbox.ConvertByteArrayToString(resultStream.ToArray()); So that creates the full request to be sent  to Companies House. Sending the request So far we have a string with a request for the Companies House service. Now we need to send the request to the Companies House Service. Configuration within an Azure project There are entire blog entries written about configuration within an Azure project – most of this is out of scope for this article but the following is a summary. Configuration is defined in two files within the parent project *.csdef which contains the definition of configuration setting. <?xml version="1.0" encoding="utf-8"?> <ServiceDefinition name="OnlineCompanyHub" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceDefinition"> <WebRole name="CompanyHub.Host"> <InputEndpoints> <InputEndpoint name="HttpIn" protocol="http" port="80" /> </InputEndpoints> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" /> <Setting name="DataConnectionString" /> </ConfigurationSettings> </WebRole> <WebRole name="CompanyHub.Services"> <InputEndpoints> <InputEndpoint name="HttpIn" protocol="http" port="8080" /> </InputEndpoints> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" /> <Setting name="SenderId"/> <Setting name="SenderPassword" /> <Setting name="GovTalkUrl"/> </ConfigurationSettings> </WebRole> <WorkerRole name="CompanyHub.Worker"> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" /> </ConfigurationSettings> </WorkerRole> </ServiceDefinition>   Above is the configuration definition from the project. What we are interested in however is the ConfigurationSettings tag of the CompanyHub.Services WebRole. There are four configuration settings here, but at the moment we are interested in the second to forth settings; SenderId, SenderPassword and GovTalkUrl The value of these settings are defined in the ServiceDefinition.cscfg file; <?xml version="1.0"?> <ServiceConfiguration serviceName="OnlineCompanyHub" xmlns="http://schemas.microsoft.com/ServiceHosting/2008/10/ServiceConfiguration"> <Role name="CompanyHub.Host"> <Instances count="2" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="DataConnectionString" value="UseDevelopmentStorage=true" /> </ConfigurationSettings> </Role> <Role name="CompanyHub.Services"> <Instances count="2" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="UseDevelopmentStorage=true" /> <Setting name="SenderId" value="UserID"/> <Setting name="SenderPassword" value="Password"/> <Setting name="GovTalkUrl" value="http://xmlgw.companieshouse.gov.uk/v1-0/xmlgw/Gateway"/> </ConfigurationSettings> </Role> <Role name="CompanyHub.Worker"> <Instances count="2" /> <ConfigurationSettings> <Setting name="DiagnosticsConnectionString" value="UseDevelopmentStorage=true" /> </ConfigurationSettings> </Role> </ServiceConfiguration>   Look for the Role tag that contains our project name (CompanyHub.Services). Having configured the parameters we can now transmit the request. This is done by ‘POST’ing a stream of XML to the Companies House servers. govTalkUrl = RoleEnvironment.GetConfigurationSettingValue("GovTalkUrl"); request = WebRequest.Create(govTalkUrl); request.Method = "POST"; request.ContentType = "text/xml"; writer = new StreamWriter(request.GetRequestStream()); writer.WriteLine(RequestMessage); writer.Close(); We use the WebRequest object to send the object. Set the method of sending to ‘POST’ and the type of data as text/xml. Once set up all we do is write the request to the writer – this sends the request to Companies House. Did the Request Work Part I – Getting the response Having sent a request – we now need the result of that request. response = request.GetResponse(); reader = response.GetResponseStream(); result = Toolbox.ConvertByteArrayToString(Toolbox.ReadFully(reader));   The WebRequest object has a GetResponse() method which allows us to get the response sent back. Like many of these calls the results come in the form of a stream which we convert into a string. Did the Request Work Part II – Translating the Response Much like XSLT and XML were used to create the original request, so it can be used to extract the response and by deserializing the result we create an object that contains the response. Did it work? It would be really great if everything worked all the time. Of course if it did then I don’t suppose people would pay me and others the big bucks so that our programmes do not a) Collapse in a heap (this is an area of memory) b) Blow every fuse in the place in a shower of sparks (this will probably not happen this being real life and not a Hollywood movie, but it was possible to blow the sound system of a BBC Model B with a poorly coded setting) c) Go nuts and trap everyone outside the airlock (this was from a movie, and unless NASA get a manned moon/mars mission set up unlikely to happen) d) Go nuts and take over the world (this was also from a movie, but please note life has a habit of being of exceeding the wildest imaginations of Hollywood writers (note writers – Hollywood executives have no imagination and judging by recent output of that town have turned plagiarism into an art form). e) Freeze in total confusion because the cleaner pulled the plug to the internet router (this has happened) So anyway – we need to check to see if our request actually worked. Within the GovTalk response there is a section that details the status of the message and a description of what went wrong (if anything did). I have defined an XSLT template which will extract these into an XML document. <?xml version="1.0"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ev="http://www.govtalk.gov.uk/CM/envelope" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <xsl:template match="/"> <GovTalkStatus xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <Status> <xsl:value-of select="ev:GovTalkMessage/ev:Header/ev:MessageDetails/ev:Qualifier"/> </Status> <Text> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Text"/> </Text> <Location> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Location"/> </Location> <Number> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Number"/> </Number> <Type> <xsl:value-of select="ev:GovTalkMessage/ev:GovTalkDetails/ev:GovTalkErrors/ev:Error/ev:Type"/> </Type> </GovTalkStatus> </xsl:template> </xsl:stylesheet>   Only thing different about previous XSL files is the references to two namespaces ev & gt. These are defined in the GovTalk response at the top of the response; xsi:schemaLocation="http://www.govtalk.gov.uk/CM/envelope http://xmlgw.companieshouse.gov.uk/v1-0/schema/Egov_ch-v2-0.xsd" xmlns="http://www.govtalk.gov.uk/CM/envelope" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" xmlns:gt="http://www.govtalk.gov.uk/schemas/govtalk/core" If we do not put these references into the XSLT template then  the XslCompiledTransform object will not be able to find the relevant tags. Deserialization is a fairly simple activity. encoder = new ASCIIEncoding(); ms = new MemoryStream(encoder.GetBytes(statusXML)); serializer = new XmlSerializer(typeof(GovTalkStatus)); xmlTextWriter = new XmlTextWriter(ms, Encoding.ASCII); messageStatus = (GovTalkStatus)serializer.Deserialize(ms);   We set up a serialization object using the object type containing the error state and pass to it the results of a transformation between the XSLT above and the GovTalk response. Now we have an object containing any error state, and the error message. All we need to do is check the status. If there is an error then we can flag an error. If not then  we extract the results and pass that as an object back to the calling function. We go this by guess what – defining an XSLT template for the result and using that to create an Xml Stream which can be deserialized into a .Net object. In this instance the XSLT to create the result of a Company Number Search is; <?xml version="1.0" encoding="us-ascii"?> <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ev="http://www.govtalk.gov.uk/CM/envelope" xmlns:sch="http://xmlgw.companieshouse.gov.uk/v1-0/schema" exclude-result-prefixes="ev"> <xsl:template match="/"> <CompanySearchResult xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <CompanyNumber> <xsl:value-of select="ev:GovTalkMessage/ev:Body/sch:NumberSearch/sch:CoSearchItem/sch:CompanyNumber"/> </CompanyNumber> <CompanyName> <xsl:value-of select="ev:GovTalkMessage/ev:Body/sch:NumberSearch/sch:CoSearchItem/sch:CompanyName"/> </CompanyName> </CompanySearchResult> </xsl:template> </xsl:stylesheet> and the object definition is; using System; using System.Collections.Generic; using System.Linq; using System.Web; namespace CompanyHub.Services { public class CompanySearchResult { public CompanySearchResult() { CompanyNumber = String.Empty; CompanyName = String.Empty; } public String CompanyNumber { get; set; } public String CompanyName { get; set; } } } Our entire code to make calls to send a request, and interpret the results are; String request = String.Empty; String response = String.Empty; GovTalkStatus status = null; fault = null; try { using (CompanyNumberSearchRequest requestObj = new CompanyNumberSearchRequest()) { requestObj.PartialCompanyNumber = CompanyNumber; request = Toolbox.CreateRequest(requestObj, "CompanyNumberSearch.xsl"); response = Toolbox.SendGovTalkRequest(request); status = Toolbox.GetMessageStatus(response); if (status.Status.ToLower() == "error") { fault = new HubFault() { Message = status.Text }; } else { Object obj = Toolbox.GetGovTalkResponse(response, "CompanyNumberSearchResult.xsl", typeof(CompanySearchResult)); } } } catch (FaultException<ArgumentException> ex) { fault = new HubFault() { FaultType = ex.Detail.GetType().FullName, Message = ex.Detail.Message }; } catch (System.Exception ex) { fault = new HubFault() { FaultType = ex.GetType().FullName, Message = ex.Message }; } finally { } Wrap up So there we have it – a reusable set of functions to send and interpret XML results from an internet based service. The code is reusable with a little change with any service which uses XML as a transport mechanism – and as for the Companies House GovTalk service all I need to do is create various objects for the result and message sent and the relevent XSLT files. I might need minor changes for other services but something like 70-90% will be exactly the same.

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  • OCR: How to improve accuracy - existing libraries for removing non-text 'furniture', shapes, etc to

    - by Rob
    I want to remove rectangles etc that enclose text in a screenshot image, so that I can perform optical character recognition to get accurate text from the screenshot. Background: I doing this to extract data from a legacy application for use with other applications. This is the only way to get at this data as associated files are in a closed, proprietary, binary format. I will be using AutoItScript to drive the application to show data in its UI, then I will screenshot this and feed this to tesseract. I've already had some success in automating the UI, and have been able to use tesseract to get plain ascii text out of the bitmap. There are several AutoItScripr forum articles discussing its use with tesseract/OCR but not specifically for my question. http://www.autoitscript.com/forum/index.php?s=6c32c3ece12756e635a619cdf175eff9&showforum=2 What I need to do There are thin, 1-pixel wide rectangles that closely enclose some text, when fed to tesseract, it sees them as I for example for a verticle line of the rectangle. Any thoughts on how to remove the rectangles, or best practices? I'm asking if there is a generic command line based toolset to overwrite rectangles, for example, in .png files. I could then pass the .png through this, then pass it to tesseract. Details on the tesseract release/setup I've used are as follows: Go here: http://code.google.com/p/tesseract-ocr/downloads/list - For the basic english generic character set to get Tesseract up and running and recognising your bitmapped text into ascii text, use tesseract-2.00.eng.tar.gz (current version at time of writing is: "English language data for Tesseract (2.00 and up) Jul 2007 989 KB 84845") Related questions I have already looked at on Stack Overflow http://stackoverflow.com/questions/1335581/how-to-give-best-chance-of-success-to-an-ocr-software http://stackoverflow.com/questions/2296568/analysis-and-transformation-of-the-image-on-the-basis-of-this-analysis-for-better http://stackoverflow.com/questions/2268028/reading-characters-off-of-the-screen In these, my question is not completely answered or a commercial solution is being sold. I do not want to consider a commercial solution at this stage.

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  • CGBitmapContextCreate issue while trying to resize images

    - by Jeff
    Hello! I'm running into an issue when I try to create a CGContextRef while attempting to resize some images: There are the errors Sun May 16 20:07:18 new-host.home app [7406] <Error>: Unable to create bitmap delegate device Sun May 16 20:07:18 new-host.home app [7406] <Error>: createBitmapContext: failed to create delegate. My code looks like this - (UIImage*) resizeImage:(UIImage*)originalImage withSize:(CGSize)newSize { CGSize originalSize = originalImage.size; CGFloat originalAspectRatio = originalSize.width / originalSize.height; CGImageRef cgImage = nil; int bitmapWidth = newSize.width; int bitmapHeight = newSize.height; CGColorSpaceRef colorspace = CGColorSpaceCreateDeviceRGB(); CGContextRef context = CGBitmapContextCreate(nil, bitmapWidth, bitmapHeight, 8, bitmapWidth * 4, colorspace, kCGImageAlphaPremultipliedLast); if (context != nil) { // Flip the coordinate system //CGContextScaleCTM(context, 1.0, -1.0); //CGContextTranslateCTM(context, 0.0, -bitmapHeight); // Black background CGRect rect = CGRectMake(0, 0, bitmapWidth, bitmapHeight); CGContextSetRGBFillColor (context, 0, 0, 0, 1); CGContextFillRect (context, rect); // Resize box to maintain aspect ratio if (originalAspectRatio < 1.0) { rect.origin.y += (rect.size.height - rect.size.width / originalAspectRatio) * 0.5; rect.size.height = rect.size.width / originalAspectRatio; } else { rect.origin.x += (rect.size.width - rect.size.height * originalAspectRatio) * 0.5; rect.size.width = rect.size.height * originalAspectRatio; } CGContextSetInterpolationQuality(context, kCGInterpolationHigh); // Draw image CGContextDrawImage (context, rect, [originalImage CGImage]); // Get image cgImage = CGBitmapContextCreateImage (context); // Release context CGContextRelease(context); } CGColorSpaceRelease(colorspace); UIImage *result = [UIImage imageWithCGImage:cgImage]; CGImageRelease (cgImage); return result; }

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  • C code won't compile

    - by cc
    Please help me to understand why the following code will not compile: #include <stdio.h> //#include <iostream> //using namespace std; int main(void){ int i,k,x,y,run,e,r,s,m,count=0; char numbers[19][19]; for(i=0;i<19;i++){ for (k=0;k<19;k++){ numbers[i][k]='.'; } } void drawB(){ printf(" 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 \n"); printf ("0 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[0][0],numbers[0][1],numbers[0][2],numbers[0][3],numbers[0][4], numbers[0][5],numbers[0][6],numbers[0][7],numbers[0][8],numbers[0][9], numbers[0][10],numbers[1][11],numbers[1][12],numbers[1][13],numbers[0][14] ,numbers[0][15],numbers[0][16],numbers[0][17],numbers[0][18]); printf ("1 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[1][0],numbers[1][1],numbers[1][2],numbers[1][3],numbers[1][4], numbers[1][5],numbers[1][6],numbers[1][7],numbers[1][8],numbers[1][9], numbers[1][10],numbers[1][11],numbers[1][12],numbers[1][13],numbers[1][14] ,numbers[1][15],numbers[1][16],numbers[1][17],numbers[1][18]); printf ("2 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" numbers[2][0],numbers[2][1],numbers[2][2],numbers[2][3],numbers[2][4], numbers[2][5],numbers[2][6],numbers[2][7],numbers[2][8],numbers[2][9], numbers[2][10],numbers[2][11],numbers[2][12],numbers[2][13],numbers[2][14] ,numbers[2][15],numbers[2][16],numbers[2][17],numbers[2][18]); printf ("3 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[3][0],numbers[3][1],numbers[3][2],numbers[3][3],numbers[3][4], numbers[3][5],numbers[3][6],numbers[3][7],numbers[3][8],numbers[3][9], numbers[3][10],numbers[3][11],numbers[3][12],numbers[3][13],numbers[3][14] ,numbers[3][15],numbers[3][16],numbers[3][17],numbers[3][18]); printf ("4 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[4][0],numbers[4][1],numbers[4][2],numbers[4][3],numbers[4][4], numbers[4][5],numbers[4][6],numbers[4][7],numbers[4][8],numbers[4][9], numbers[4][10],numbers[4][11],numbers[4][12],numbers[4][13],numbers[4][14] ,numbers[4][15],numbers[4][16],numbers[4][17],numbers[4][18]); printf ("5 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[5][0],numbers[5][1],numbers[5][2],numbers[5][3],numbers[5][4], numbers[5][5],numbers[5][6],numbers[5][7],numbers[5][8],numbers[5][9], numbers[5][10],numbers[5][11],numbers[5][12],numbers[5][13],numbers[5][14] ,numbers[5][15],numbers[5][16],numbers[5][17],numbers[5][18]); printf ("6 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[6][0],numbers[6][1],numbers[6][2],numbers[6][3],numbers[6][4], numbers[6][5],numbers[6][6],numbers[6][7],numbers[6][8],numbers[6][9], numbers[6][10],numbers[6][11],numbers[6][12],numbers[6][13],numbers[6][14] ,numbers[6][15],numbers[6][16],numbers[6][17],numbers[6][18]); printf ("7 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[7][0],numbers[7][1],numbers[7][2],numbers[7][3],numbers[7][4], numbers[7][5],numbers[7][6],numbers[7][7],numbers[7][8],numbers[7][9], numbers[7][10],numbers[7][11],numbers[7][12],numbers[7][13],numbers[7][14] ,numbers[7][15],numbers[7][16],numbers[7][17],numbers[7][18]); printf ("8 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[8][0],numbers[8][1],numbers[8][2],numbers[8][3],numbers[8][4], numbers[8][5],numbers[8][6],numbers[8][7],numbers[8][8],numbers[8][9], numbers[8][10],numbers[8][11],numbers[8][12],numbers[8][13],numbers[8][14] ,numbers[8][15],numbers[8][16],numbers[8][17],numbers[8][18]); printf ("9 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[9][0],numbers[9][1],numbers[9][2],numbers[9][3],numbers[9][4], numbers[9][5],numbers[9][6],numbers[9][7],numbers[9][8],numbers[9][9], numbers[9][10],numbers[9][11],numbers[9][12],numbers[9][13],numbers[9][14] ,numbers[9][15],numbers[9][16],numbers[9][17],numbers[9][18]); printf ("0 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[10][0],numbers[10][1],numbers[10][2],numbers[10][3],numbers[10][4], numbers[10][5],numbers[10][6],numbers[10][7],numbers[10][8],numbers[10][9], numbers[10][10],numbers[10][11],numbers[10][12],numbers[10][13],numbers[10][14] ,numbers[10][15],numbers[10][16],numbers[10][17],numbers[10][18]); printf ("1 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[11][0],numbers[11][1],numbers[11][2],numbers[11][3],numbers[11][4], numbers[11][5],numbers[11][6],numbers[11][7],numbers[11][8],numbers[11][9], numbers[11][10],numbers[11][11],numbers[11][12],numbers[11][13],numbers[11][14] ,numbers[11][15],numbers[11][16],numbers[11][17],numbers[11][18]); printf ("2 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[12][0],numbers[12][1],numbers[12][2],numbers[12][3],numbers[12][4], numbers[12][5],numbers[12][6],numbers[12][7],numbers[12][8],numbers[12][9], numbers[12][10],numbers[12][11],numbers[12][12],numbers[12][13],numbers[12][14] ,numbers[12][15],numbers[12][16],numbers[12][17],numbers[12][18]); printf ("3 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[13][0],numbers[13][1],numbers[13][2],numbers[13][3],numbers[13][4], numbers[13][5],numbers[13][6],numbers[13][7],numbers[13][8],numbers[13][9], numbers[13][10],numbers[13][11],numbers[13][12],numbers[13][13],numbers[13][14] ,numbers[13][15],numbers[13][16],numbers[13][17],numbers[13][18]); printf ("4 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[14][0],numbers[14][1],numbers[14][2],numbers[14][3],numbers[14][4], numbers[14][5],numbers[14][6],numbers[14][7],numbers[14][8],numbers[14][9], numbers[14][10],numbers[14][11],numbers[14][12],numbers[14][13],numbers[14][14] ,numbers[14][15],numbers[14][16],numbers[14][17],numbers[14][18]); printf ("5 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[15][0],numbers[15][1],numbers[15][2],numbers[15][3],numbers[15][4], numbers[15][5],numbers[15][6],numbers[15][7],numbers[15][8],numbers[15][9], numbers[15][10],numbers[15][11],numbers[15][12],numbers[15][13],numbers[15][14] ,numbers[15][15],numbers[15][16],numbers[15][17],numbers[15][18]); printf ("6 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[16][0],numbers[16][1],numbers[16][2],numbers[16][3],numbers[16][4], numbers[16][5],numbers[16][6],numbers[16][7],numbers[16][8],numbers[16][9], numbers[16][10],numbers[16][11],numbers[16][12],numbers[16][13],numbers[16][14] ,numbers[16][15],numbers[16][16],numbers[16][17],numbers[16][18]); printf ("7 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[17][0],numbers[17][1],numbers[17][2],numbers[17][3],numbers[17][4], numbers[17][5],numbers[17][6],numbers[17][7],numbers[17][8],numbers[17][9], numbers[17][10],numbers[17][11],numbers[17][12],numbers[17][13],numbers[17][14] ,numbers[17][15],numbers[17][16],numbers[17][17],numbers[17][18]); printf ("8 %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c %c \n\n" ,numbers[18][0],numbers[18][1],numbers[18][2],numbers[18][3],numbers[18][4], numbers[18][5],numbers[18][6],numbers[18][7],numbers[18][8],numbers[18][9], numbers[18][10],numbers[18][11],numbers[18][12],numbers[18][13],numbers[18][14] ,numbers[18][15],numbers[18][16],numbers[18][17],numbers[18][18]); } void checkSurrounded (int x,int y){ //numbers [x-1,y-1 ] , numbers [x-1,y ] , numbers [x-1,y+1 ] //numbers [x,y-1 ] , numbers [x,y ] , numbers [x,y+1 ] //numbers [x+1,y-1, ] , numbers [x+1,y ] , numbers [x+1,y+1 ] if(numbers[x][y]=='A'){ if((numbers[x-1][y-1]=='B') && (numbers[x-1][y]=='B') && (numbers[x-1][y+1]=='B') && (numbers[x][y-1]=='B') && (numbers[x][y+1]=='B') && (numbers[x+1][y-1]=='B') && (numbers[x+1][y]=='B')){ numbers[x][y]='B';} } if(numbers[x][y]=='B'){ if((numbers[x-1][y-1]=='A') && (numbers[x-1][y]=='A') && (numbers[x-1][y+1]=='A') && (numbers[x][y-1]=='A') && (numbers[x][y+1]=='A') && (numbers[x+1][y-1]=='A') && (numbers[x+1][y]=='A')){ numbers[x][y]='A'; } } } /** void checkArea(){ //detect enemy stone //store in array //find adjacent enemy stones // store the enemy stones in the array //keep on doing this until there are no more enemy stones that are adjacent for (s=0;s<19;s++) { for (m=0;m<19;m++) { if (numbers[s][m]=='A'){ count++; } } } }//end fn void checkAdjacent(int x, int y){ if (numbers [x][y]=='A'){ if((numbers[x][y-1]=='B' && numbers [x-1][y]=='B' && numbers[x][y+1]=='B' && numbers[x+1][y]=='B')){ } } } void getUserInput(){ int run=1; while(run){ printf("Enter x coordinate\n"); scanf("%d",&x); printf("Enter y coordinate\n"); scanf("%d",&y); if((x>18 || y>18 || x<0 || y<0) && !( numbers[x][y]=='.' )){ printf("invalid imput\n"); } else{ numbers[x][y]='B'; run=0; drawB(); } } } */ void getCupInput(){ //go through borad //starting from [0][0] //stop at first player stone //save as target x and target y //surround target x and target y //if already surrounded //start looking in borad again from last position //at end of board reset to [0][0] for(s=0;s<19;s++) { for(m=0;m<19;m++) { if (numbers[s][m]==0){ count++; } } } x=x-2; y=y+2; numbers[x][y]='A'; drawB(); } while(1){ //getUserInput(); getCupInput(); } system("pause"); return 0; }

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  • CGContextSetShadow() - shadow direction reversed between iOS 3.0 and 4.0?

    - by Pascal
    I've been using CGContextSetShadowWithColor() in my Quartz drawing code on the iPhone to generate the "stomped in" look for text and other things (in drawRect: and drawLayer:inContext:). Worked perfectly, but when running the exact same code against iOS 3.2 and now iOS 4.0 I noticed that the shadows are all in the opposite direction. E.g. in the following code I set a black shadow to be 1 pixel above the text, which gave it a "pressed in" look, and now this shadow is 1px below the text, giving it a standard shadow. ... CGContextSetShadowWithColor(context, CGSizeMake(0.f, 1.f), 0.5f, shadowColor); CGContextShowGlyphsAtPoint(context, origin.x, origin.y, glyphs, length); ... Now I don't know whether I am (or have been) doing something wrong or whether there has been a change to the handling of this setting. I haven't applied any transformation that would explain this to me, at least not knowingly. I've flipped the text matrix in one instance, but not in others and this behavior is consistent. Plus I wasn't able to find anything about this in the SDK Release Notes, so it looks like it's probably me. What might be the issue?

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  • iphone - making the CGAffineTransform permanent

    - by Mike
    I am banging my head on the wall here due to this problem: When I create a UIImageView this view has a certain orientation and size. Lets call this state "A". This view responds to taps. It can be dragged around the screen. At some point in the code I apply a CGAffineTransform to the view. Does not matter if the affine is a scale, a rotation, a translation or a combination of all. Does not matter also if the transform is absolute or relative. Not to mention the device can change its orientation and the view is autorotated to the correct orientation (that we can cay is a kind of rotation or transformation applied to the view). The problem is: the moment I touch that object or try to animate its transparency or any other parameter, it "remembers" the state "A" and does all animations from that state, not from current state. If I simply touch the view, it returns instantly to state "A". The code is not doing it by itself. It is an annoying "gift" from Apple. How to I make a view assume its current state of transformations as the reset or initial state? In other words, how do I make a view forget its past transformations or states? The only way I know is recreating the view, but this is a ridiculous way of doing this. Is there any way to make this work as I described? thanks

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  • Manual drag-drop operations in Flex

    - by Yarin
    This is a two-part problem: A) I'm implementing several irregular drag-drop operations in Flex (e.g. DataGrid ItemRenderer into Tree). My preference was modifying DragManager operations to meet my needs, and in fact using DragManager allows me to do everything I need, but I'm having serious issues with performance. For example, dragging anything over a many-columned DataGrid, whether the drag was initiated with DragManager.doDrag, or just using native ListBase drag-drop functionality, slows the drag movement to a crawl. Even if the DataGrid is disabled/ not listenening for any move/drag events, this happens. On the other hand, if the drag is initiated by calling .startDrag() on the Sprite, the drag is smooth and performs great over DataGrids and everything else. So part A would be: Is there a reason why .startDrag() operations work so well, while drags initiated through DragManager.doDrag suffer so badly when over certain components? B) If indeed the solution is to handle drag-drops using .startDrag(), how would I go about determining what component the mouse is over when the drag is released? In my example, my dragged object is brought up to the top level of the display list, and so is being moved around in stage coordinates. mouseMove, mouseOver events don't fire on the components I'm dragging over because the mouse is constantly over the dragged component, so I would need some sort of stage.coordinate - visibleComponentAtThatCoordinate conversion. Any thoughts on this? Thanks alot!-- Yarin

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  • What is the target color profile in Image.FromFile?

    - by Jan Zich
    I am curious what the useEmbeddedColorManagement parameter in System.Drawing.Image.FromFile actually does. This parameter directory corresponds to a GDI+ parameter in the same method of the same class. So debugging .NET source does not lead anywhere. If my understanding of color profiles is correct, a color profile is basically a mapping which describes how particular RGB triples (or CMYK or something else) map into the so called Profile Connection Space (CIELAB or CIEXYZ). Now, if I open an image with embedded color in .NET setting useEmbeddedColorManagement to true, my experience is I get an image whose RGB values are not exactly the same as the original values in the file, i.e. is transformed. Since the original image was an RGB and the new is also an RGB, there must have been a transformation from the embedded color profile to a Profile Connection Space and the back to RGB. The thing which I don’t understand is what is the target color system? Is it some default Windows color profile? Is the current monitor profile? Is it sRGB?

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  • Constant NSDictionary/NSArray for class methods.

    - by Jeff B
    I am trying to code a global lookup table of sorts. I have game data that is stored in character/string format in a plist, but which needs to be in integer/id format when it is loaded. For instance, in the level data file, a "p" means player. In the game code a player is represented as the integer 1. This let's me do some bitwise operations, etc. I am simplifying greatly here, but trying to get the point across. Also, there is a conversion to coordinates for the sprite on a sprite sheet. Right now this string-integer, integer-string, integer-coordinate, etc. conversion is taking place in several places in code using a case statement. This stinks, of course, and I would rather do it with a dictionary lookup. I created a class called levelInfo, and want to define the dictionary for this conversion, and then class methods to call when I need to do a conversion, or otherwise deal with level data. NSString *levelObjects = @"empty,player,object,thing,doohickey"; int levelIDs[] = [0,1,2,4,8]; // etc etc @implementation LevelInfo +(int) crateIDfromChar: (char) crateChar { int idx = [[crateTypes componentsSeparatedByString:@","] indexOfObject: crateChar]; return levelIDs[idx]; } +(NSString *) crateStringFromID: (int) crateID { return [[crateTypes componentsSeparatedByString:@","] objectAtIndex: crateID]; } @end Is there a better way to do this? It feels wrong to basically build these temporary arrays, or dictionaries, or whatever for each call to do this translation. And I don't know of a way to declare a constant NSArray or NSDictionary. Please, tell me a better way....

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  • gnuplot: display only the roots.

    Hi, Gnuplot, a great package ... I'm in love with it. But we can have our tiffs as well, as any couple :-) This time, I wanted to simply plot the roots of an equation: say a quadratic to keep things simple. However, I only want two nice round dots appearing on the x-axis representing the point where the quadratic crosses the x-axis or y=0 axis. In other words the roots (when they are real that is). I don't want to do this with datafile ... I want gnuplot to calculate the roots and plot them. First off, my attempts: single points aren't really what gnuplot would have you plot, it likes a good wide range of values. Preferably filling up the whole width of your canvas. It's possible to locate a rectangle at a certain coordinate on your plot, but I wanted a round point. Currently I'm chasing up how to do a tiny filled polygon at that point. I have tried the "samples" option bu it doesn't seem useful. Also though about defining a dirac-delta function so that only one point would be highlighted (though two would be needed). ANy suggestions welcome, thanks.

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  • Programmatically creating vector arrows in KML

    - by mettadore
    Does anyone have any practical examples of programmatically drawing icons as vectors in KML? Specifically, I have data with a magnitude and an azimuth at given coordinates, and I would like to have icons (or another graphical element) generated based on these values. Some thoughts on how I might approach it: Image directory (a brute force way): Make an image director of 360 different image files (probably batch rotate a single image) each pointing in a cooresponding azimuth. I've seen things like "Excel to KML," but am looking for code that I can use within a program, rather than a web utility. Issue: Arrow does not contain magnitude context, so that would have to be a label. I'd rather dynamically lengthen the arrow. Line creation in KML: Perhaps create a formula that creates a line with the origin at the coordinate points, with the length of the line proportional to the magnitute, and angled according to azimuth. There would then be two more lines, perhaps 30 degrees or so extending from the end of the previous line to make the arrow head. Issues: Not a separate image icon, so not sure how it would work in KML. Also not sure how easy it would be to generate this algorithm. Separate image generation: Perhaps create a PHP file that uses imagemagick or something similar to dynamically generate a .png file in a similar method to the above, and then link to the icon using the URI "domain.tld/imagegen.php?magnitude=magvalue&azimuth=azmvalue". Issue: Still have the problem of actually writing the algorithm for image generation. So, the question: has anyone else come up with solutions for programmatic vector (rather than merely arrow) generation?

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  • How do I code Citrix web sites to use a Secure Gateway (CSG)?

    - by RAVolt
    I'm using Citrix's sample code as a base and trying to get it to generate ICA files that direct the client to use their Secure Gateway (CSG) provider. My configuration is that the ICA file's server address is replaced with a CSG ticket and traffic is forced to go to the CSG. The challenge is that both the Citrix App Server (that's providing the ICA session on 1494) and the CSG have to coordinate through a Secure Ticket Authority (STA). That means that my code needs to talk to the STA as it creates the ICA file because STA holds a ticket that the CSG needs embedded into the ICA file. Confusing? Sure! But it's much more secure. The pre-CSG code looks like this: AppLaunchInfo launchInfo = (AppLaunchInfo)userContext.launchApp(appID, new AppLaunchParams(ClientType.ICA_30)); ICAFile icaFile = userContext.convertToICAFile(launchInfo, null, null); I tried to the SSLEnabled information to the ICA generation, but it was not enough. here's that code: launchInfo.setSSLEnabled(true); launchInfo.setSSLAddress(new ServiceAddress("CSG URL", 443)); Now, it looks like I need to register the STA when I configure my farm: ConnectionRoutingPolicy policy = config.getDMZRoutingPolicy(); policy.getRules().clear(); //Set the Secure Ticketing Authorities (STAs). STAGroup STAgr = new STAGroup(); STAgr.addSTAURL(@"http://CitrixAppServerURL/scripts/ctxsta.dll"); //creat Secure Gateway conenction SGConnectionRoute SGRoute = new SGConnectionRoute(@"https://CSGURL"); SGRoute.setUseSessionReliability(false); SGRoute.setGatewayPort(80); SGRoute.setTicketAuthorities(STAgr); // add the SGRoute to the policy policy.setDefault(SGRoute); This is based on code I found on the Citrix Forums; however, it breaks my ability to connect with the Farm and get my application list! Can someone point me to an example of code that works? Or a reference document?

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